Analytical and clinical performance evaluation of a new NT-proBNP assay.

BACKGROUND: The study evaluated the performance of the Mindray N-terminal pro-B-type natriuretic peptide (NT-proBNP) in a healthy population in China, focusing on creating a reference range for future clinical applications adjusted according to different demographics. METHODS: The study measured NT-proBNP in 2277 healthy individuals. We analyzed age and sex-stratified data, performed precision, accuracy, linearitcvy, and detection limit studies, and evaluated method comparison and consistency between Roche and Mindray assays on 724 serum samples. We used Excel 2010, Medcalc, and GraphPad Prism 9. RESULTS: In males, the 97.5th centile NT-proBNP concentration at age < 45, 45 to 54, 55 to 64, 65 to 74 and ≧ 75 were 89.4 ng/L, 126 ng/L, 206 ng/L, 386 ng/L and 522 ng/L, respectively. In females, the concentration of NT-proBNP at the same age was 132 ng/L, 229 ng/L, 262 ng/L, 297 ng/L and 807 ng/L, respectively. The repeatability precision coefficient of variation (CV%) for NT-proBNP was between 0.86 and 1.65 in analytical performance. In contrast, the reproducibility precision (CV%) for NT-proBNP was between 1.52 and 3.22, respectively. The study found a bias of accuracy of 3.73% in low-value samples (concentration: 148.69) and 7.31% in high-value samples (concentration: 1939.08). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 125 ng/L were 96.6%, 92.3%, 84.2%, and 98.5%, respectively. In contrast, those of 300 ng/L were 94.0%, 98.2%, 95.7% and 97.5%, respectively. CONCLUSIONS: The Mindray NT-proBNP assay showed increased levels in both males and females with age, with higher levels in women. It performs well and aligns with manufacturer specifications. We recommend adjusting cutoff values based on demographic factors.

Performance verification of a biochemical detection system for hydrothorax and ascites and clinical diagnostic accuracy evaluation of exudate and tuberculous effusion.

Background: Lactate dehydrogenase (LDH), total protein (TP) and glucose (Glu) in pleural hydrothorax and ascites can be used in the diagnosis of exudate, and adenosine deaminase (ADA) can be used in the diagnosis of tuberculous effusion. However, the manufacturers do not claim that their biochemical reagents can be used to detect hydrothorax and ascites samples. Therefore, medical laboratories must conduct suitability studies on biochemical reagents for hydrothorax and ascites samples to comply with regulatory requirements for humor detection. This study aimed to verify the analytical performance and clinical diagnostic accuracy of the Mindray biochemical reagents, including LDH, TP, Glu and ADA, for hydrothorax and ascites. Methods: The repeatability, detection limits and reference intervals of Mindray biochemical reagents (LDH, TP, Glu, ADA) in detecting hydrothorax and ascites were determined. The comparison of different measurement procedures was performed. Meanwhile, the diagnostic accuracy of LDH, TP, Glu and ADA were assessed. Results: The quality control results of LDH, TP, Glu, and ADA were all under control. The repeatability coefficient of variation (%) of LDH, TP, Glu, and ADA were all less than 1%. The limits of blank of LDH, TP, Glu, and ADA were 0.33 U/L, 0.45 g/L, 0.00 mmol/L, and 0.04 U/L, respectively; the limits of detection were 1.57 U/L, 1.85 g/L, 0.05 mmol/L, and 0.12 U/L, respectively. Compared with the reference measurement program, the correlation coefficients of LDH, TP, Glu and ADA were 0.9931, 0.9983, 0.9996 and 0.9966, respectively; the regression equations were y=1.0082x-10.06, y=0.9965x-0.4732, y=0.9903x+0.0522 and y=1.0051x-0.0232, respectively. The reference intervals of LDH, TP, Glu, and ADA in hydrothorax and ascites were ≤198.39 U/L, ≤32.97 g/L, ≥5.03 mmol/L. and ≤11.00 U/L respectively. For differentiating between exudates and transudates, the area under the curve (AUC) of LDH, TP, and Glu were 0.913, 0.875, and 0.767, respectively; the AUC of ADA for the differential diagnosis of tuberculous and nontuberculous effusions was 0.876. Conclusions: The LDH, TP, Glu, and ADA assays were validated for use with the Mindray BS-2800 analyzer for hydrothorax and ascites evaluation. LDH, TP, and Glu in hydrothorax and ascites are applicable to the differential diagnosis of exudates and transudates; ADA in hydrothorax and ascites can be employed to differentiate and diagnose tuberculous and nontuberculous effusions.

Electronic nose for odor monitoring at a landfill fenceline: Training and validation of a model for real-time odor concentration measurement.

In recent years, electronic noses, or more generally Instrumental Odor Monitoring Systems (IOMS), have aroused increasing interest in the field of environmental monitoring. One of the most interesting applications of these instruments is the real-time estimation of the odor concentration at plant fencelines to continuously monitor odor emissions and identify anomalous conditions. In this type of application, it is possible to setting a "warning" threshold, enabling the continuous check of proper functioning of the plant and sudden intervention in case of malfunctions, preventing, at the same time, the risk of odor events at the receptors. For this purpose, it is necessary to provide a continuous, fast and reliable measurement of the odor concentration, which is nowadays one of the main challenges of this technology. In this context, this work proposes the development of a quantification model for quantifying odors detected at the fenceline of a landfill characterized by very different odor fingerprints. A double-step quantification model, firstly identifying the different odor classes to which the ambient air monitored at the fenceline by the IOMS belong to, and then developing different specific PLS regression models for each of the odor classes identified, was developed. The results of the proposed quantification model were compared to the ones obtained developing a "global" quantification model, which implements the regression on the globality of the training set, without differentiating between the odor classes. Then, they were further evaluated by comparison with the odor events detected at the sensitive receptor by another electronic nose. Moreover, the combined evaluation of the odor events at the plant fenceline and the receptor, respectively, together with the meteorological data highlighted the need of identifying variable warning thresholds for the odor concentrations at the fenceline according to effectively account for meteorological conditions and produce an output that is more correlated with the probability that an odor is perceived outside of the plant.

Development of a novel biochar-made porous monolith for enhanced C1 and H2 fermentation.

Biochar is a carbonaceous porous material that is produced through the thermal processing of biomass under oxygen-limited environment. Nevertheless, biochar is known to be an inexpensive and sustainable raw material with a wide range of possible applications. Recently, biochar has been discovered as an efficient biological catalyst for anaerobic conversion, mainly due to its highly porous structure with micro and macro channels, which procures a viable living area for attached-grown microorganisms. Whereas it is never applied to improve the biological conversion of gas substances such as C1 (e.g., CO, CO2) and H2, which is a promising research area with increasing commercial interest. However, considering that biological reaction is limited by the target water solubility of gas substrates, special attention is required when combining biochar for gas fermentation. The goal was to create a novel gas sparger where the biofilm grows on biochar, thus improving the interaction with the gaseous substrate. For this purpose, polystyrene foam and powdered biochar were compounded to form a mouldable composite, which was then cast as a porous monolith.•Biochar-made sparger (BS) was investigated for the homoacetogenic conversion of H2 gas via microbial mixed cultures as opposed to a control test equipped with a stone sparger.•BS showed a significantly better performance in terms of biological gas fixation rate (36% more than control) and productivity (8.5 gCOD L-1 d-1).

Clinical application of a new method for determination of the erythrocyte sedimentation rate using the BC-720 automated hematology analyzer.

BACKGROUND: The erythrocyte sedimentation rate (ESR) is a nonspecific inflammatory indicator and is widely used in clinical diagnosis. Westergren is the gold standard method recommended by the International Committee for Standardization of Hematology (ICSH), but it is time-consuming and inconvenient and has biosafety risks. A new alternate method for ESR (Easy-W ESR) measurement was designed and integrated into the Mindray BC-720 series automated hematology analyzer to meet the clinical needs of hematology laboratories for efficiency, safety, and automation. In this study, the performance of the new ESR method was evaluated based on the ICSH recommendations on modified and alternate ESR methods. METHODS: Methodological comparisons using the BC-720 analyzer, TEST 1, and the Westergren method were performed to assess repeatability, carryover, sample stability, reference range validation, factors influencing the ESR, and clinical applicability in rheumatology and orthopedics. RESULTS: The correlation between the BC-720 analyzer and the Westergren method was good (Y = 2.082 + 0.9869X, r = 0.9657, P > 0.0001, n = 342), carryover was <1%, the repeatability standard deviation was ≤1 mm/h, and the coefficient of variation (CV) was ≤5%. The reference range meets the manufacturer's claim. For rheumatology patients, the BC-720 analyzer showed a good correlation with the Westergren method (Y = 1.021X-1.941, r = 0.9467, n = 149). For orthopedic patients, the BC-720 analyzer also showed a good correlation with the Westergren method (Y = 1.037X + 0.981, r = 0.978, n = 97). CONCLUSION: This study verified the clinical and analytical performance of the new ESR method, indicating that the results are very similar to those obtained using the Westergren method.

Analytical performance verification protocols and specifications of CD34 +cell enumeration by flow cytometry / 中华检验医学杂志

Objective:To investigate the analytical performance verification protocols and performance specifications of CD34+cell enumeration by flow cytometry for clinical laboratories.Methods:According to international guidelines and National Health Standard of China, we designed the performance verification protocols of CD34 +cell enumeration (including percent count and absolute count) by flow cytometry. Four quality assessment materials, three leukapheresis products and three samples of peripheral blood were selected to verify the precision, linearity, carryover, trueness and accuracy of FACSCanto Ⅱ measurement system, and the assessment criterion was set according to the detection technologies of clinical laboratories. Results:The CVs of intra-run precision of percent count and absolute count were 2.5% to 8.9% and 3.0% to 9.0%; the CVs of inter-run precision were 2.8% to 10.5% and 3.8% to 9.9%, respectively. The slopes of linearity regression equation of low range (3.6/μl to 123.6/μl) and high range (113.2/μl to 1196.3/μl) were 0.993 2 and 0.965 2, and R2 were 0.999 6 and 0.993 9, and the biases were -8.67% to 0.22%. The carryover of percent and absolute count were 0.07% and 0.00%. When percent count≤0.2% or absolute count≤20/μl, the absolute biases of trueness were in the range of ±0.006% or ±0.5/μl, and the absolute biases of accuracy were in the range of ±0.02% or ±0.9/μl; when percent count>0.2% or absolute count>20/μl, the relative biases of trueness were in the range of ±5.65%, and the relative biases of accuracy were in the range of ±8.19%. The verification results met the assessment criterion set in this study. Conclusions:The performance verification protocols and assessment criterion formulated in this study not only conform to the recommendations of domestic and foreign guidelines, but also conform to state of the detection technologies of native clinical laboratories, which can be taken as a reference of performance verification for clinical laboratories.

Performance verification of domestic nucleic acid testing system in blood stations based on T/CSBT / 中国输血杂志

【Objective】 To explore the performance verification of the Shengxiang automatic NAT system for HBV DNA, HCV RNA and HIV RNA-1 using PCR-fluorescence in the laboratories of blood stations, in order to meet the requirements of T/CSBT and ensure the quality of nucleic acid detection. 【Methods】 Samples used in the external quality assessment (EQA) of National Center for Clinical Laboratories of the year 2022 were taken to verify the concordance. The standard materials of HBV DNA, HCV RNA and HIV RNA-1 were used to verify the analytical sensitivity, endogenous interfering substances, repeatability, anti-cross contamination ability and stability. 【Results】 The concordance rate of 20 EQA samples was 100%. The analytical sensitivity of HBV DNA, HCV RNA and HIV RNA-1 were all reactive and met T/CSBT. The yielding of HBV DNA, HCV RNA and HIV RNA-1 was affected little with lipemia at 3g/L and hemolysis at 4g/L. The coefficients of variation(CV) of intra-assay and inter-assay which met T/CSBT were all less than 5%, and the intra-assay variation coefficient was less than the inter-assay variation coefficient. The test results of 40 negative samples tested for cross contamination resistance were 100% negative, and 40 positive samples of HBV with 10 000 IU/mL were 100% positive. The stability verification results showed that the detection rate of weak positive samples was 100%. The coefficient of variation of the test results of the reagent after 1 and 5 freeze-thaw cycles were less than 5%,and the difference between the detection Ct value of reagent underwent once freeze-thaw and five-time freeze-thaw was not statistically significant. 【Conclusion】 The analytical sensitivity,endogenous interfering substances, repeatability,anti-cross contamination ability,stability and the compliance rate of domestic Shengxiang Gene automatic NAT system and supporting reagents by PCR-fluorescence method all meet T/CSBT, so it can be used for nucleic acid detection in blood screening in blood station laboratory.

Performance evaluation of nucleic acid testing system for blood screening in high-altitude areas / 中国输血杂志

【Objective】 To validate the performance of a nucleic acid testing(NAT) system for blood screening in the high-altitude Nagqu region of Tibet, in order to assess the capability of NAT in high-altitude areas and further enhance blood safety. 【Methods】 Various methods were employed to evaluate the analytical sensitivity, reproducibility, ability to prevent cross-contamination, and comparison between different NAT systems. 【Results】 The NAT system in the Nagqu region of Tibet achieved a 100% detection rate for high-concentration HBV DNA and HIV-1 RNA samples, and over 90% for medium-concentration samples. PROBIT analysis revealed the lower limits of detection (LOD) for HBV DNA and HIV-1 RNA to be 8.29 IU/mL (95% CI, 5.88~20.55 IU/mL) and 40.52 IU/mL (95% CI, 30.26~85.92 IU/mL), respectively. For HCV RNA genotype 2a, the LOD was 97.14 IU/mL (95% CI, 71.00~182.67 IU/mL), all of which were lower than the declared minimum detectable concentrations in the instructions. Reproducibility analysis demonstrated a 100% level of consistency within the system. Cross-contamination performance verification showed a strong ability to resist cross-contamination. Comparative analysis of repeated testing of low-concentration HBV DNA samples and multi-system testing in plain areas revealed consistency rates of 77.78%(14/18) and 77.27%(17/22), respectively, indicating certain differences between the NAT system in Nagqu region and other systems. 【Conclusion】 The NAT system exhibited excellent performance in blood screening at high altitudes. The results of performance validation in high-altitude blood screening NAT systems were largely consistent with those in plain areas, providing a reliable basis for enhancing blood safety in high-altitude regions.

Performance verification experiment for enzyme-linked immunosorbent assay in blood screening laboratory / 中国输血杂志

【Objective】 To verificate the performance of enzyme-linked immunosorbent assay (ELISA) in blood screening laboratory. 【Methods】 The repeatability, precision, sensitivity, specificity, compliance, detection limit and anti-interference of ELISA items in the laboratory detection system were verified. 【Results】 The repeatability was 100%.The intra batch imprecision of each system was less than 10%, and the inter batch imprecision was less than 15%. The sensitivity, specificity and compliance were 100%, with the minimum detection limits of the two reagents at 0.75 NCU/mL and 0.25 NCU/mL respectively, The anti-interference met the requirements of the reagent manual. 【Conclusion】 The analysis of the performance verification data of ELISA test items will help continuously improve the performance of detection system and ensure the safety of clinical blood use.

Performance verification of five commercial RT-qPCR diagnostic kits for SARS-CoV-2.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has caused a global pandemic beginning in 2020, can be detected by reverse-transcription polymerase chain reaction (RT-PCR). However, owing to the urgent need for a large number of detection kits, the time spent researching and developing these kits has been shortened during the pandemic, and the kits that are being used commercially have not undergone full and independent evaluation. To ensure the accuracy of SARS-CoV-2 test results, performance verification of commercial Real-Time quantitative PCR (RT-qPCR) kits is required. METHODS: The performance of five commercial RT-qPCR diagnostic kits for SARS-CoV-2 used in China was evaluated using a coronavirus disease 2019 (COVID-19) RNA liquid performance verification reference product-manufactured by Guangzhou Bondson (BDS) Biotechnology Co., Ltd.,Guangzhou, China-that uses droplet digital RT-PCR technology combined with fluorescence quantitative PCR. The five kits of Novel Coronavirus 2019-nCoV nucleic acid detection kit (RT-qPCR method) evaluated were Da An (Da An Gene Co., Ltd. of Sun Yat-sen University), Liferiver (Shanghai ZJ Bio-Tech Co., Ltd.), Kinghawk (Beijing Kinghawk Pharmaceutical Co., Ltd.), eDiagnosis (Wuhan Easy Diagnosis Biomedicine Co., Ltd.), and Maccura (Maccura Biotechnology Co., Ltd.). Performance verification criteria included the coincidence rate, limit of detection (LoD), cross-reactivity, precision, and anti-interference. Finally, through the BDS performance verification reference product kit, clinical samples are used to verify its clinical diagnostic efficacy. RESULTS: The coincidence rate was 100% for all kits except for Kinghawk, which was 95%. The LoD for Da An, eDiagnosis and Maccura was 250copies/mL, and it was 1000 copies/ml for Liferiver. Kinghawk was not able to detect its advertised LoD of 500 copies/ml. The cross-reactivity test results were all negative. Moreover, all kits had a coefficient of variation less than 5%; however, Liferiver showed the best precision. Da An, Liferiver, and eDiagnosis showed higher sensitivity to the nucleocapsid (N) gene than they did to the open reading frame (ORF) 1ab genes. Anti-interference results for all five kits were positive. The results of clinical diagnostic efficacy were that the specificity of the four kits was 1.000 (0.877-1.000), the sensitivity of Da An was 1.000 (0.850-1.000), Liferiver was 0.964 (0.798-0.998), Maccura was 0.893 (0.706-0.972), and eDiagnosis was 0.857 (0.664-0.953). CONCLUSIONS: All commercial RT-qPCR diagnostic kits for SARS-CoV-2 passed the BDS performance verification, except for Kinghawk (batch No:20200608113) which failed to detect the LoD of 500 copies/mL. Da An and Liferiver have excellent clinical diagnostic specificity and sensitivity. This study can provide guidance for the selection or optimization of RT-qPCR diagnostic test kits for SARS-CoV-2.

Performance verification of nucleic acid testing project based on ISO 15189 / 中国输血杂志

【Objective】 To explore the performance verification of NAT and its procedures for HBV DNA, HCV RNA and HIV RNA-1 using PCR-fluorescence via Cobas s201 automatic NAT system and supporting MPX V2.0 reagents that applied in the laboratories of blood stations, in order to satisfy ISO 15189 accreditation requirements and ensure the accuracy of NAT results. 【Methods】 Samples used in external quality assessment(EQA) of year 2020 were taken to verify the concordance, Performance evaluation panel and sensitivity verification panel of Roche second-generation NAT system were used to verify the sensitivity/ specificity and the lower limit of detection, respectively.And HBV DNA, HCV RNA and HIV RNA-1 quality control products were used to verify the anti-interference ability. 【Results】 The concordance rate of 40 EQA, samples was 100%. The sensitivity and specificity of Cobas s201 automatic NAT system and supporting MPX V2.0 reagents in detecting HBV DNA, HCV RNA and HIV RNA-1 were all 100%. The lower detection limit for HBV DNA, HCV RNA and HIV RNA-1 all met the requirements of reagent instructions. The yielding of HBV DNA, HCV RNA and HIV RNA-1 were affected little with hemolysis at 500 mg/dL but interfered seriously as lipemia reached 3 300 mg/dL. 【Conclusion】 The concordance rate, sensitivity, specificity and lower detection limit of the Cobas s201 fully-automatic NAT system and MPX V2.0 reagents by PCR-fluorescence method all met the requirements of reagent instructions. The verification of anti-interference ability demonstrated the requirements of ISO 15189 and the needs of blood station laboratories could be satisfied, and the detection methods and procedures can ensure the accuracy of NAT results.

Development of quantum dot-based fluorescence lateral flow immunoassay strip for rapid and quantitative detection of serum interleukin-6.

BACKGROUND: Interleukin-6 (IL-6) is an inflammatory factor that increases rapidly in response to infectious diseases including sepsis. The aim of this study is to develop a quantum dot (QD)-based fluorescence lateral flow immunoassay (LFIA) strip that can rapidly and accurately detect IL-6 levels. METHODS: QD-based LFIA strips were fabricated by conjugating CdSe/ZnS QDs to the IL-6 antibody. Performance verification and clinical sample analysis were carried out to evaluate the newly developed strip. RESULTS: QD-based LFIA strips were successfully fabricated. The test strip's linear range was 10-4000 pg/ml, with a linear correlation coefficient of R2  ≥ .959. The sensitivity of the test strip was 1.995 pg/ml. The recovery rate was 95.72%-102.63%, indicating satisfying accuracy. The coefficient of variation (CV) of the intra-assay was 2.148%-3.903%, while the inter-assay was 2.412%-5.293%, verifying the strip's high precision. The cross-reaction rates with various interleukins (IL-1α, IL-1ß, IL-2, IL-4, and IL-8) and interferon-γ (IFN-γ) were all <0.1%. When the strip was placed in a 50°C oven for 1, 2, 3, and 4 weeks, the test results were not significantly altered compared to storage at room temperature. Furthermore, 200 clinical serum samples were analyzed to compare the strip with the Beckman chemiluminescence immunoassay (CLIA) kit, which revealed a high correlation (n = 200, R2  = .9971) for the detection of IL-6. CONCLUSIONS: The QD-based test strip can rapidly and quantitatively detect IL-6 levels, thus meeting the requirement of point-of-care test (POCT) and showing excellent clinical prospects.

Performance verification of a new fibrinogen assay.

BACKGROUND: Plasma fibrinogen (FIB), also known as factor I, plays a key role in the coagulation process. FIB testing in a clinical laboratory is crucial for coagulation screening and thrombolytic therapy. Here, we assessed the performance of a new, Chinese-made coagulation analyzer in the detection of FIB by comparing its precision and clinical feasibility with that of an imported system. METHODS: Blood samples were collected and plasmas were separated. The precision, linearity, reference interval, carryover rate, clinically reportable range, and clinical applicability of the domestic coagulation analyzer for FIB assay were assessed and validated based on the documents or industry standards issued by the United States Clinical and Laboratory Standards Institute (CLSI). RESULTS: The within-batch precision CVs (coefficient of variation) for the low- and high-level specimens were 2.92% and 0.24%, respectively, while the total precision CVs were 3.05% and 1.81%, respectively; all of them met the experimental requirements. The linear range was validated to cover 1.0-6.5 g/L, and a good linear relationship was obtained within the measurement range (R2=0.9998). The reference interval was verified for adults and the carryover rate was also evaluated to be 0.68%. The clinically reportable range was 0.33-13.0 g/L. With a sample size of 180 cases, the methodological comparison showed a correlation coefficient (r) of 0.9886 between Mindray ExC810 and Sysmex CS5100. Furthermore, when the level of FIB was higher than 4.0 g/L or lower than 1.0 g/L, the 2 systems had an agreement rate of 100%. CONCLUSIONS: Mindray ExC810 has a good performance for FIB assay in terms of precision, linearity, reference interval, carryover rate, and clinically reportable range. Methodological study showed that Mindray ExC810 has good agreement with Sysmex CS5100 and meets the requirements of laboratory testing. Therefore, Mindray ExC810 is suitable for FIB assay in clinical laboratory.

A comparative study on the performance of the extraction of 2019-NCOV RNA by three kinds of automated nucleic acid purifiers / 公共卫生与预防医学

Objective To compare the detection results of three kinds of automated nucleic acid purifiers, and to evaluate the detection performance of the domestic 2019-nCoV RNA purifier. Methods Three automated nucleic acid purifiers, namely A (imported), B (domestic), and C (domestic) automated nucleic acid extraction instruments, were used to purify nucleic acid. The Conchestan 2019-nCoV RNA (Liquid) quality control product S5 (batch number 202007002, reference level 1000cp/ml) was chosen as the experimental object. The quality control product was diluted in a series of 10 to 1000 times to prepare experimental samples of different concentrations. Among them, the A nucleic acid purifier used its own matching reagents, and the B and C purifiers belonged to a same manufacturer with different models and used their own supporting reagents as well as third-party reagents, to evaluate the anti-pollution ability, precision, accuracy, repeatability, detection limit and linear correlation. Results Using the imported brand A as a reference standard for comparison, when using reagents from B, the linear correlation between the two domestic nucleic acid purifiers and the imported equipment were 0.999, 0.915 (N-terminal), and 0.997, 0.825 (ORF1ab-terminal), respectively; when using the third-patty reagents, the linear correlation between the two domestic nucleic acid purifiers and the imported equipment were 0.999, 0.915 (N-terminal) and 0.997, 0.825 (ORF1ab-terminal), respectively. Conclusion The extraction of 2019-NCOV RNA by domestic nucleic acid purifiers can be fully automated with good correlation. The system performance is comparable to international standards. Moreover, the extraction time of the domestic nucleic acid purifiers is shorter than the imported one, which offers obvious advantages when the number of samples is large.

Validation and evaluation of Roche Cobas S201 system in blood screening for nucleic acid detection and amplification / 中国输血杂志

【Objective】 To verify the key performance parameters of Roche Cobas S201 multiplex NAT for blood donors, so as to provide data for the conformation of multiplex NAT performance and establish a scientific and feasible verification scheme. 【Methods】 Comprehensive performance verification on four key parameters of ROCHE COBAS S201 multiplex NAT system, including the 95% detection limit, compliance rate, anti-interference ability and operator comparison were conducted. The data were compared with the specifications provided by the manufacturer to evaluate the performance of laboratory testing system and ensure the quality of blood testing. 【Results】 2 sets of COBAS S201 multiplex NAT system in our laboratory were used to perform 5 times of the 95% detection limit value declared by the manufacturer for individual tests. The experimental results showed that the target NAT can be detected 100% and the lower limit of determination was verified. Single-virus NAT was performed to detect 5 different HBV DNA concentrations (25 ~400 IU/mL), 5 different HCV RNA concentrations (25 ~400 IU/mL), 5 different HIV RNA Concentration (100~1 000 IU/mL), and 5 negative tubes. The experimental results showed that all detected values of 20 tubes were 100% consistent with the true value, and the performance parameter "coincidence rate" was verified. Samples containing lipoemia, hemolysis, with ALT>50 mL/L and syphilis-positive endogenous interfering substances with 3 times of the 95% detection limit value were tested for 3 times, and results showed both response rate (3/3) and yielding rate reached 100%. In the control group (with none or in the normal range of interfering substances), reactivity was detected in samples with extremely low concentration of 3 times of the 95% detection limit, showing no significant difference (P>0.05). Above results fully showed that the existence of interference substances (lipidemia, hemolysis, ALT ≥ 50 and syphilis positive) in the blood of donors had no significant effect on the yielding of HBV/HCV/HIV virus target nucleic acids. Different operators performed the sample loading tests with same instrument, reagent and specimen showed 100% consistency in the results. It could be preliminarily assessed that there was no difference in the operations between the operators in this verification. 【Conclusion】 The verification scheme of the multiplex NAT system for methodology performance index (95% detection limit, coincidence rate, anti-interference ability, and operator comparison) established in this study, showed simple, flexible, scientific and feasible characteristics and could provide reference and data support for domestic blood transfusion services in acid detection.

Study on performance verification of enzyme-linked immunosorbent assay in blood screening laboratory / 中国输血杂志

【Objective】 To validate the performance of enzyme-linked immunosorbent assay (ELISA) for the detection of antigens and antibodies for blood-borne diseases, so as to meet the requirements of blood screening laboratories. 【Methods】 The reproducibility, precision, sensitivity, specificity, conformance and detection limit of ELISA reagents under different detection procedures were verified according to relevant standards and reagent instructions. 【Results】 The performance verification results of the test procedures were in line with the relevant standards and laboratory requirements. 【Conclusion】 The performance of ELISA method can meet the relevant standards and requirements, as well as the application requirements of the laboratory. Through the analysis and comparison of the performance verification data, the blood screening laboratory can better understand the performance indicators of the detection system, continuously improve the performance of the detection system, and ensure the safety of clinical blood use.

Performance verification of four nucleic acid detection systems: A comparitve study / 中国输血杂志

【Objective】 To compare the analytical performance of Tigris, Panther, ChiTaS BSS1200 and cobas S201 system to see if they satisfy the requirements of blood screening and to know the concordance of the results presented by these four systems. 【Methods】 According to the relevant documents of ISO15189 and Standard Operating Procedure of Blood Station(2019), the parameters needed to be verified for nucleic acid tests(NAT) included: analytical sensitivity verification, system compare test, anti-jamming capability and anti-cross-contamination ability. 【Results】 The 95% detection limits of Tigris, Panther, ChiTaS BSS1200 and Cobas S201 for HBV-DNA(IU/mL), HIV-RNA(IU/mL) and HCV-RNA(IU/mL) were 2.013 vs 4 vs 2.995 vs 0.99, 13.039 vs 10.21 vs 30.952 vs 32.24, and 2.278 vs 2.077 vs 12.008 vs 3.39, respectively. In the performance comparison verification between NAT systems, the results of the two sets of Tigris systems were in full accordance with serum plate, with a concordance rate of 100%, Kappa value of 1, and none cross-contamination.The concordance rate of No.1 Panther system was 100%, and No.2 98%, with Kappa value of 0.961 and none cross-contamination. Hemolytic samples (5g/L Hb concentration) and lipemic blood samples (13.81 mmol/L TG concentration) had no significant effect on the detection of low-concentration samples. 【Conclusion】 No significant differences in the performance of NAT systems were notable by devices, as the four systems were fully automated with high sensitivity, which can fully satisfy the blood screening requirements. Panther system demonstrates superior analysis sensitivity in HCV-RNA/HIV-RNA and lower in HBV DNA, but also in required criteria, as compared to Tigris system. Neither hemolysis nor lipemic blood had any significant effect on the test results.

Evaluation of the Autof MS1000 mass spectrometer in the identification of clinical isolates.

BACKGROUND: To evaluate the accuracy and performance of the Autof MS1000 mass spectrometer in bacteria and yeast identification, 2342 isolates were obtained from microbial cultures of clinical specimens (e.g. blood, cerebrospinal fluid, respiratory tract samples, lumbar puncture fluid, wound samples, stool, and urine) collected in 2019 in Henan Provincial People's Hospital. Repetitive strains from the same patient were excluded. We tested the Autof MS1000 and Bruker Biotyper mass spectrometry systems and the classical biochemical identification system VITEK 2/API 20C AUX. Inconsistencies in strain identification among the three systems were identified by 16S rDNA and gene sequencing. RESULTS: At the species level, the Autof MS1000 and Bruker Biotyper systems had isolate identification accuracies of 98.9 and 98.5%, respectively. At the genus level, the Autof MS1000 and Bruker Biotyper systems were 99.7 and 99.4% accurate, respectively. The instruments did not significantly differ in identification accuracy at either taxonomic level. The frequencies of unreliable identification were 1.1% (26/2342) for the Autof MS1000 and 1.5% (34/2342) for the Bruker Biotyper. In vitro experiments demonstrated that the coincidence rate of the Autof MS1000 mass spectrometer in the identification of five types of bacteria was > 93%, the identification error rate was < 3%, and the no identification rate was 0. This indicates that the Autof MS1000 system is acceptable for identification. CONCLUSIONS: The Autof MS1000 mass spectrometer can be utilised to identify clinical isolates. However, an upgradation of the database is recommended to correctly identify rare strains.

Performance verification of anti-SARS-CoV-2-specific antibody detection by using four chemiluminescence immunoassay systems.

OBJECTIVES: The purpose of the current study was to evaluate the analytical performance of seven kits for detecting IgM/IgG antibodies against coronavirus (SARS-CoV-2) by using four chemiluminescence immunoassay systems. METHODS: Fifty patients diagnosed with SARS-CoV-2 infection and 130 controls without coronavirus infection from the General Hospital of Chongqing were enrolled in the current retrospective study. Four chemiluminescence immunoassay systems, including seven IgM/IgG antibody detection kits for SARS-CoV-2 (A_IgM, A_IgG, B_IgM, B_IgG, C_IgM, C_IgG and D_Ab), were employed to detect antibody concentrations. The chi-square test, the receiver operating characteristic (ROC) curve and Youden's index were determined to verify the cut-off value of each detection system. RESULTS: The repeatability verification results of the A, B, C and D systems are all qualified. D_Ab performed best (92% sensitivity and 99.23% specificity), and B_IgM performed worse than the other systems. Except for the A_IgM and C_IgG systems, the optimal diagnostic thresholds and cut-off values of the other kits and their recommendations are inconsistent with each other. B_IgM had the worst AUC, and C_IgG had the best diagnostic accuracy. More importantly, the B_IgG system had the highest false-positive rate for testing patients with AIDS, tumours and pregnancies. The A_IgM system test showed the highest false-positive rates among elderly individuals over 90 years old. COVID-2019 IgM/IgG antibody test systems exhibit performance differences. CONCLUSIONS: The Innodx Biotech Total Antibody serum diagnosis kit is the most reliable detection system for anti-SARS-CoV-2 antibodies, which can be used together with nucleic acid tests as an alternative method for SARS-CoV-2 detecting.

Use of Miniature Step Gauges to Assess the Performance of 3D Optical Scanners and to Evaluate the Accuracy of a Novel Additive Manufacture Process.

In this work, we show how miniature step gauges featuring unidirectional and bidirectional lengths can be used to assess the performance of 3D optical scanners as well as the accuracy of novel Additive Manufacturing (AM) processes. A miniature step gauge made of black polyphenylene sulfide (PPS) was used for the performance verification of three different optical scanners: a structured light scanner (SLS), a laser line scanner (LLS), and a photogrammetry-based scanner (PSSRT), having comparable resolutions and working volumes. Results have shown a good agreement between the involved scanners, with errors below 5 µm and expanded uncertainties below 10 µm. The step gauge geometry due to the bidirectional lengths, highlights that there is a different interaction between the optical properties of the step gauge under measurement and each optical instrument involved and this aspect has to be considered in the uncertainty budget. The same geometry, due to its great significance in the detection of systematic errors, was used, as a novelty, to evaluate the accuracy of Lithography-based Ceramics Manufacturing (LCM), a proprietary additive manufacturing technology used for the fabrication of medical implants. In particular, two miniature step gauges made of Tricalcium Phosphate (TCP) were produced. Measurements conducted with the SLS scanner were characterized by a negligible error and by an uncertainty of about 5 µm. Deviations of the manufactured step gauges with respect to the Computer Aided Designed (CAD) model were comprised between ±50 µm, with positive deviations in the order of 100 µm on vertical sides. Differences in the order of 50 µm between the two step gauges were registered.