Preparation of national reference panel of HBV for nucleic acid testing donor screening / 中国生物制品学杂志

@#Objective To prepare the national reference panel of hepatitis B virus(HBV) for nucleic acid testing(NAT)donor screening.Methods A number of plasma samples from donors positive for HBV antibody and patients with HBV infection collected from blood centers,plasma stations and biological products companies in Shanghai,Gansu,Henan,Hunan,Hubei and other regions were tested for HBV DNA viral load agent,and negative and positive reference candidates were screened;The HBV DNA national standard was diluted to 10~3 IU/ml with human negative plasma,as a candidate for limit of detection(LOD).National negative and positive reference candidates of HBV for NAT donor screening and LOD reference to be calibrated were distributed to 8 enterprise laboratories for joint detection of HBVHCVHIV NAT donor screening.The homogeneity and stability of the national reference panel were investigated.Results A total of 8 negative samples with HBV viral load of 0 were screened as negative references and 9 positive samples with viral load of 10~3～10~4 IU/mL were used as positive references;One LOD reference was calibrated with WHO HBV DNA standard,and the virus content was 1.0 × 10~3 IU/ml.The national reference panel showed good stability and the homogeneity inspection met the requirements.Conclusion The national reference panel of HBV DNA for NAT donor screening was prepared,which provided a basis for the quality control and standardization of HBV DNA reagents for donor screening.

A Simple Proposition for Improving Industrial Hygiene Air Sampling Methods

When conducting an exposure assessment, the primary goal of the industrial hygienist is to fully characterize the worker's exposure during a work shift to compare it with an occupational exposure limit. This applies regardless of the duration of the work activity as an activity that is relatively short in duration can still present exposure in excess of the occupational exposure limit even when normalized over an 8-hr shift. This goal, however, is often impeded by the specification of a minimum sample volume in the published sampling method, which may prevent the sample from being collected or submitted for analysis. Removing the specification of minimum sample volume (or adjusting it from a requirement to a recommendation), in contrast, allows for a broader assessment of jobs that consist of short-duration and high-exposure activities and also eliminates the unnecessary practice of running sampling pumps in clean air to collect a specified, minimum volume.

Comparison of three lod determination approaches in tlc / 中国药学杂志

OBJECTIVE: To compare the limits of detection ( LODs) of TLC obtained with three evaluation approaches in Chinese Pharmacopoeia 2015, and facilitate selection of LOD evaluation approach in TLC method validation. METHODS: After development, the spots of strychnine, berberine hydrochloride, and ten chemical dyes were first detected by human eyes and then scanned by thin layer scanner to obtain the LODs based on visual evaluation, signal-to-noise, and standard deviation of the response and the slope. RESULTS: The LODs obtained by the three approaches showed no significant difference. For strychnine and 10 chemical dyes, the LODs based on the three approaches were close to each other. For berberine hydrochloride, the LOD obtained by visual evaluation was slightly lower than those obtained by the other two approaches. CONCLUSION: All the three approaches are feasible to determine LOD in TLC. The approach based on visual evaluation is rapid and reliable, which might be the first choice for LOD determination in TLC.

Establishing and Verifing Detection Limit for the Eight Items before Blood Transfusion with Enzyme-Linked Immunosorbent Assay by the WS/T 514-2017 Industry Standard Documents / 现代检验医学杂志

Objective To evaluate the limit of detection of eight enzyme-linked immunosorbent assay (ELISA) according to hospital grade assessment and ISO15189:2012.Methods According to the new health industry standard WS/T 514-2017:"Establishment and verification of detection capability for clinical laboratory measurement procedures",the limit of detection (LoD) was established,in the sameset of detection system,using two reagent lot,each lot for 5 consecutive days 4 consecutive days to assess the value of the concentration of five specimens were detected repeatedly,calculated the corresponding hit rate,then transform into probability units,and the corresponding concentration value production regression model,the hit rate of 95 ％ corresponds to the probability unit 1.645 substituted into the equation,the resulting concentration value was LoD estimates.The detection limit values were tested for 3 consecutive days of detection of two LoD concentrations near the declared concentration of the sample (diluted by the standard material) was detected 4 times repeatedly to calculate the positive result was greater than or equal to the percentage of LoD statement,greater than or equal to the critical value of 87％,then verified success.Results HBsAg:0.100 IU/ml,HBsAb:9.642 mIU/ml,HBeAg:0.666 NCU/ml,HBeAb:3.700 NCU/ml,HBcAb:0.786 IU /ml,HCV:0.506 NCU/ml,TP:2.236 mIU/ml and HIV:0.135 NCU/ml.The detection limit estimates were passed.Conclusion The verification limit of the verification project in the testing method and detection system of the laboratory meet the requirements Objective.

Application and evaluation of multiple cross displacement amplification in detection of Listeria monocytogenes / 中国人兽共患病学报

Listeria monocytogenes is a significant food-borne pathogen that is capable of causing severe listeriosis in both humans and animals.Traditional techniques such as culture-based approaches have good specificity and sensitivity,while they are time-consuming and tend to be tedious.Hence,we presented a simple and rapid molecular technique using multiple cross displacement amplification (MCDA) targeting L.monocytogenes-specific gene lmo0733 for sensitive and specific detection of the pathogen.L.monocytogenes-MCDA assay used a set of ten primers spanning ten distinct regions of target sequence and was carried out at a constant temperature 61 ℃ to evaluate the specificity,sensitivity and feasibility.A total of three methods were used to confirm MCDA products,including color change of Loopamp Fluorescent Detection Reagent,real-time measurement of turbidity and agarose gel electrophoresis.The limit of detection (LoD) of the MCDA was 10 fg DNA,which was 25-fold and 250-fold more sensitive than that of the LAMP and CPA assay for detecting L.monocytogenes DNA,respectively.The detection ability of MCDA method was identical to the culture-biotechnical method for 153 rat intestinal feces samples,and was better than LAMP,CPA and conventional PCR.The results in this study indicated that the MCDA assay could be used as a rapid,sensitive and effective tool for the detection of L.monocytogenes in the food industry,medical institutions and field.

Establishment of Detection Limit and Clinical Reportable Range for Detection of Anti-HBs by Chemiluminescence Method / 现代检验医学杂志

Objective To establish detection limit and clinical reportable range for detection of anti-HBs by chemiluminescence method and evaluate by clinical application.Methods Referring to the Clinical and Laboratory Standards Institute (CLSI) relevant documents,the programme of blank limit (LoB),detection limit (LoD),quantitative detection limit (LoQ),analytical range of measurement (AMR),clinical reportable range (CRR) for detection of anti-HBs by chemiluminescence method,were designed and measured.The established clinical reportable range and maximum dilution were used to predict the recovery stage of acute hepatitis B patients and to evaluate the effectiveness of different vaccines.Results LoB,LoD,LoQ,AMR and CRR for detection of anti-HBs by chemiluminescence method were 0.87,1.89,3.0,0～970.50 and 3.0 ～48 525 mIU/ml respectively,and the maximum dilution was 1 ∶ 50.The patient with acute hepatitis B showed elevated anti-HBs at fourth weeks after treatment (CRR).The anti-HBs mean was the highest in the B vaccine of the three vaccines.Conclusion The establishment of detection limit and clinical reportable range for detection of anti-HBs by chemiluminescence method was better meet the requirements of clinical laboratories,provide reliable results for clinical laboratories.

Establishment and Evaluation of Blank Limit,Detection Limint and Quantitation Limit of Fecal Occult Blood Tests with Colloidal Gold Method Based on the Document of EP-1 7A2 / 现代检验医学杂志

Objective To explore colloidal gold method used to detect fecal occult blood tests(FOB)detection capability and establish the laboratory standard operation of detecting FOB limit of blank(LOB),limit of detection (LOD)and quantifica-tion limit (LOQ)according to the CLSI document《Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures;Approved Guideline-Second Edition》(EP17-A2),in order to reduce the false negative rate of the weakly positive samples,and to provide a way of quantitative detection for qualitative detection of colloidal gold method.Methods Detected series of solution of hemoglobin made of dissolved fresh whole blood with the ELISA kit of human free hemoglobin,and es-tablished the standard curve of detection of FOB with colloidal gold method.Detected the blank samples and a series of low concentration samples with the colloidal gold test strip of FOB and measured the color bands by the Nato Checker710.The quantitative results obtained were statistically analysised by SPSS 1 9.0 and calculated blank limit,detection limit and quanti-fication limit.Results The LOB,LOD and LOD were 99.01,340.48 and 354.9 ng/ml according to the methods in CLSI EP1 7-A2 ducument.Conclusion The detection limits established by CLSI EP1 7-A2 document was more scientific in j udge-ment positive or negative to FOB than which used naked eye and can meet the clinical laboratory and clinical doctor require-ment better.Clinical laboratories should be strictly in detection limits of reagents in order to ensure their effectiveness,and should be generaly to other tests based on colloidal gold method.

Safety issues and new rapid detection methods in traditional Chinese medicinal materials

The safety of traditional Chinese medicine (TCM) is a major strategic issue that involves human health. With the continuous improvement in disease prevention and treatment, the export of TCM and its related products has increased dramatically in China. However, the frequent safety issues of Chinese medicine have become the 'bottleneck' impeding the modernization of TCM. It was proved that mycotoxins seriously affect TCM safety; the pesticide residues of TCM are a key problem in TCM international trade; adulterants have also been detected, which is related to market circulation. These three factors have greatly affected TCM safety. In this study, fast, highly effective, economically-feasible and accurate detection methods concerning TCM safety issues were reviewed, especially on the authenticity, mycotoxins and pesticide residues of medicinal materials.

Correctly understand and use analytical sensitivity and limit of detection / 中华检验医学杂志

Limit of detection is one of most important indicators of methodological evaluation.In consideration of the misunderstanding and incorrect differentiating sensitivity and limit of detection by clinical laboratory , equipment and reagent manufacturers and journals of laboratory medicine , this article would show detailed analysis and comparison to figure out the proper use method.

Evaluation of quantitative detection limit and functional sensitivity of prealbumin and their clinical applications analysis / 国际检验医学杂志

Objective To evaluate the limit of blank (LoB),limit of detection (LoD),limit of quantitation(LoQ)and functional sensitivity (FS)of prealbumin (PA)detected by the Roche Modular P automatic biochemical analyzer.Methods According to the EP17A file of the American Clinical and Laboratory Standards Institute (CLSI),saline as the blank sample and a series of low con-centration samples were detected by the Roche Modular P automatic biochemical analyzer for determining LoB,LoD and LoQ.And FS was determined based on the domestic universal method .Results LoB of PA was 16.35 mg/L,LoD was 18.23 mg/L,LoQ was temporarily unable to evaluate and FS was 25.00 mg/L.The report scope and the report mode in clinic were affirmed by combi-ning with the low value of the reportable scope.Conclusion LoD of PA detected by the Roche Modular P automatic biochemical an-alyzer is established,which provides more valuable information for clinical diagnosis and treatment.Conducting the comparison of different evaluation methods determines the advantages and limitation of the practical application of different methods.

Low Rates of Additional Cancer Detection by Magnetic Resonance Imaging in Newly Diagnosed Breast Cancer Patients Who Undergo Preoperative Mammography and Ultrasonography / 한국유방암학회지

PURPOSE: We evaluated the efficacy of breast magnetic resonance imaging (MRI) for detecting additional malignancies in breast cancer patients newly diagnosed by breast ultrasonography and mammography. METHODS: We retrospectively reviewed the records of 1,038 breast cancer patients who underwent preoperative mammography, bilateral breast ultrasonography, and subsequent breast MRI between August 2007 and December 2010 at single institution in Korea. MRI-detected additional lesions were defined as those lesions detected by breast MRI that were previously undetected by mammography and ultrasonography and which would otherwise have not been identified. RESULTS: Among the 1,038 cases, 228 additional lesions (22.0%) and 30 additional malignancies (2.9%) were detected by breast MRI. Of these 228 lesions, 109 were suspected to be malignant (Breast Imaging-Reporting and Data System category 4 or 5) on breast MRI and second-look ultrasonography and 30 were pathologically confirmed to be malignant (13.2%). Of these 30 lesions, 21 were ipsilateral to the main lesion and nine were contralateral. Fourteen lesions were in situ carcinomas and 16 were invasive carcinomas. The positive predictive value of breast MRI was 27.5% (30/109). No clinicopathological factors were significantly associated with additional malignant foci. CONCLUSION: Breast MRI was useful in detecting additional malignancy in a small number of patients who underwent ultrasonography and mammography.

Comparación de iiferentes aproximaciones para etimar límites de detección en aanálisis de residuos de plaguicidas en alimentos / Comparison of different approache to estimate limits of detection for pesticide residues analysis in food / Comparaão de differentes abordagens par estimar os limites de detecçãoo na análise de resíduos de pesticidas em alimentos

El cálculo de los límites de detección (LD) es una práctica que ha generado diversas discusiones en la comunidad científica, debido a las diferentes definiciones y los procedimientos para realizar su estimación. En este estudio se aplicaron, confirmaron y compararon seis de los métodos más empleados en la estimación de LD en el análisis de residuos de plaguicidas. Los métodos evaluados correspondieron a IUPAC (por sus siglas en ingles, International Union of Pure and Applied Chemistry), la EPA (por sus siglas en ingles, Enviroment Protection Agency), t99, raíz media cuadrática del error (RMSE), Hubaux-Vos y propagación de errores. Este estudio se realizó sobre cinco productos vegetales empleando el método QuEChERS en la determinación de 31 plaguicidas, y el análisis de las muestras se realizó mediante cromatografía líquida acoplada a espectrometría de masas. Los resultados mostraron que los LD estimados con los diferentes métodos no presentaron una variación significativa con la matriz de análisis, exceptuando el método de la EPA. Por su parte, en la comprobación de los LD se encontró que los métodos t99, RMSE y Hubaux-Vos mostraron la menor relación señal ruido (S/R<3), mientras que los métodos de IUPAC y propagación de errores presentaron las mejores relaciones S/R. Finalmente, ningún método estimó los LD para todos los compuestos con relaciones S/R adecuadas.

The limit of detection (LOD) calculation is a practice that has generated several discussions in the scientific community, due to different definitions and procedures for its estimation. The fundamental objective of the present work is to apply, confirm and compare six different recommendations suggested by official guidelines for the estimation of LOD of 31 pesticide residues in five different commodities using the QuEChERS method and ultra fast liquid chromatography coupled to mass spectrometry. The methods evaluated were IUPAC, EPA, t99, root mean square error (RMSE), Hubaux- Vos and propagation of errors. In this study it was found that limits of detection of the different approaches did not show a significant variation with the commodities tested, excluding the method of EPA. On the other hand, t99, RMSE and Hubaux methods showed the lowest signal to noise ratio (S/N<3). Furthermore, the EPA approach showed the highest S/N, while IUPAC and propagation of errors methods presented the best S/N. Finally, no method estimated the limits of detection for all compounds with ratios S /N appropriate.

O cálculo dos limites de detecção (LD) é uma prática que tem levado a várias discussões na comunidade científica, devido a diferentes definições e procedimentos para a sua estimativa. Este estudo aplicou, confirmando e comparados seis dos métodos utilizados na estimativa de LD na análise de resíduos de pesticidas. Os métodos avaliados foram para IUPAC, EPA, t99, erro médio quadrático (RMSE), Hubaux-Vos e propagação de erros. Este estudo foi realizado em cinco produtos de plantas utilizando o método de determinação de pesticidas QuEChERS 31, a análise das amostras foi realizada por espectrometria de massa de cromatografia líquida. Os resultados mostraram que o LD estimada com diferentes métodos não houve variação significativa com a matriz de análise, a não ser o método EPA. Enquanto isso, no controlo da LD-se que os métodos de t99, RMSE e Hubaux-Vos apresentaram menor relação sinal-ruído (S / N <3), enquanto os métodos de propagação de erro da IUPAC e teve as melhores relações S / R Finalmente, o LD qualquer método considerado para todos os compostos, com relações S / R adequados.

Evaluation of a Multiplex Real-time PCR Assay for the Detection of Respiratory Viruses in Clinical Specimens

BACKGROUND: In this study, we evaluated the analytical performance and clinical potential of a one-step multiplex real-time PCR assay for the simultaneous detection of 14 types of respiratory viruses using the AdvanSure RV real-time PCR Kit (LG Life Sciences, Korea). METHODS: Three hundred and twenty clinical specimens were tested with the AdvanSure RV real-time PCR Kit and conventional multiplex reverse transcription (RT)-PCR assay. The assay results were analyzed and the one-step AdvanSure RV real-time PCR Kit was compared with the conventional multiplex RT-PCR assay with respect to the sensitivity and specificity of the detection of respiratory viruses. RESULTS: The limit of detection (LOD) was 1.31 plaque-forming units (PFU)/mL for human rhinoviruses (hRVs), 4.93 PFU/mL for human coronavirus HCoV-229E/NL63, 2.67 PFU/mL for human coronavirus HCoV-OC43, 18.20 PFU/mL for parainfluenza virus 1 (PIV)-1, 24.57 PFU/mL for PIV-2, 1.73 PFU/mL for PIV-3, 1.79 PFU/mL for influenza virus group (Flu) A, 59.51 PFU/mL for FluB, 5.46 PFU/mL for human respiratory syncytial virus (hRSV)-A, 17.23 PFU/mL for hRSV-B, 9.99 PFU/mL for human adenovirus (ADVs). The cross-reactivity test for this assay against 23 types of non-respiratory viruses showed negative results for all viruses tested. The agreement between the one-step AdvanSure multiplex real-time PCR assay and the conventional multiplex RT-PCR assay was 98%. CONCLUSIONS: The one-step AdvanSure RV multiplex real-time PCR assay is a simple assay with high potential for specific, rapid and sensitive laboratory diagnosis of respiratory viruses compared to conventional multiplex RT-PCR.

Analysis of Methylmercury Concentration in the Blood of Koreans by Using Cold Vapor Atomic Fluorescence Spectrophotometry

BACKGROUND: Methylmercury is an organic form of mercury that is highly toxic to humans. Here, we present and establish a novel method to detect methylmercury concentrations in the blood of Koreans. METHODS: Methylmercury concentration was analyzed with an automated methylmercury analytic system (MERX, Brooks Rand Co., USA) using cold vapor atomic fluorescence spectrophotometry (CVAFS). A variety of biological materials were digested in methanolic potassium hydroxide solution. The analysis method was validated by examination of certified reference material (955c, National Institute of Standard and Technology, USA). We randomly selected 30 Korean adults (age 20 yr or older) to analyze total blood mercury and methylmercury concentrations. RESULTS: The detection limit and methylmercury recovery rate using this method were 0.1 pg/L and, 99.19% (range: 89.33-104.89%), respectively. The mean blood concentration of methylmercury was 4.54+/-2.15 microg/L (N=30). The mean proportion of methylmercury to the total mercury concentration was 78.27% (range: 41.37-98.80%). CONCLUSIONS: This study is the first report to analyze blood methylmercury concentration using CVAFS in Korea. We expect that this method will contribute to the evaluation of mercury exposure and the assessment of the toxicological impact of mercury in future studies.