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Objective:To establish a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) method for the direct detection of serum M protein without antibody enrichment, and to assess its detection performance.Methods:Method establishment. A total of 712 waste serum samples were collected from patients who applied for the M protein identification test in Beijing Chaoyang Hospital affiliated to Capital Medical University. The immunoglobulin light chain was obtained by reduction of IgG and IgA by TCEP, and the detection method was preliminarily determined. The waste serum samples from 20 healthy people were collected to determine the range of mass-to-charge ratios of κ and λ light chain ions. 8 parallel tubes and 8 batches were set up for intra-and inter-batch reproducibility evaluation. 10-fold, 100-fold and 200-fold diluted M protein from 23 positive samples were detected by established MALDI-TOF MS method, and its sensitivity was evaluated. 3 methods of IFE, SPE and MALDI-TOF MS were used to detect M protein simultaneously, and the coincidence rate between MALDI-TOF MS and IFE and SPE was calculated.Results:The repeatability within and between batches was 100%, respectively. The original, 10-, 100-and 200-fold dilutions of 23 M protein-positive samples were determined, and the detection limit of MALDI-TOF MS for M protein was 0.06-0.18 g/L. IFE as the gold standard, the overall coincidence rates of SPE and MALDI-TOF MS were 85.9% and 92.3%, respectively, and the positive coincidence rates of SPE and MALDI-TOF MS were 72.8% and 99.7%, respectively, of the 712 samples. Among the different types of M-proteins, MALDI-TOF-MS agreed 100% with IFE M-protein results for IgA, IgD, IgM, free light chain type and biclonal group, while the agreements of SPE for IgM, IgA and free light chain samples were only 66.7%, 58% and 19.5%, respectively. One positive sample in the IgG group was not detected by MALDI-TOF MS. 23 M-proteins positive samples were diluted by original, 10, 100 and 200 times to access the sensitivity of MALDI-TOF MS method. The coincidence rate of MALDI-TOF MS was 100% and IFE was 96% at 10-fold dilution. The coincidence rate of IFE was 28% and 23% of MALDI-TOF MS at 100-fold and 200-fold dilution, respectively.Conclusions:A MALDI-TOF MS method for the detection of serum M-proteins was successfully established. This method has the advantages of high detection throughput, fast speed, good sensitivity, specificity and coincidence rate.
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Objective:To establish a candidate reference procedure for the enumeration of cell particles in urine and applied to the multi-center performance evaluation of an automated urine formed elements analyzer.Methods:According to the standardized mannual microscopic examination of fresh non-centrifuged urine samples and the recommended reference method for enumeration of cell particles in urine published by ISLH, we established a candidate reference procedure for the enumeration of cell particles in urine. From four class A tertiary hospitals′ clinical laboratories, three rigorous trained technicians per hospital tested the same specimen respectively using the reference procedure. Each specimen was repeatedly counted 5 times, obtaining the quantitative results of cell particles were obtained in urine. Four hospitals used the established candidate reference measurement procedure and the automated urine formed elements analyzer to detect 40 to 60 urine specimens from September 2020 to January 2021, and evaluate the established reference method, meanwhile evaluate the accuracy and consistency of the each count from automated urinalysis analyzer.Results:Using the candidate reference measurement procedures, the coefficient of variation of results derived from three trained technicians per hospital was less than 6.98% (red blood cells), 6.99% (white blood cells), 13.94% (epithelial cells) and met the quality requirements. The performance evaluation results of automated urine formed elements analyzer showed that the accuracy of red blood cells, white blood cells and epithelial cells met the requirements (bias≤4.98%) and was well consistent with the reference measurement procedure ( R2≥0.989). Conclusions:A candidate reference measurement procedure for the enumeration of urine cell particles was successfully established with satisfactory precision and accuracy. This procedure was applied to multicenter performance evaluation of an automated urine formed elements analyzer with good accuracy and consistency.
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Objective:To establish the sex-, age-and season-specific (month) reference intervals (RI) for thyroid stimulating hormone (TSH) measurement by big data and indirect method in adults.Methods:TSH data of anonymous patients were collected from Beijing Chaoyang Hospital Affiliated to Capital Medical University in 2016, the data were selected and outliers were removed. Indirect methods (Hoffmann method and Bhattacharya method) were used to calculate TSH reference intervals of whole population, different genders, ages and seasons (months). TSH RI from two indirect methods of total population, selected population, physical examination population was compared with RI from reagent instruction according to reference change value ( RCV) based on biological variability. Results:A total of 61 599 records were obtained from 90 699 records including 18 776 males and 42 823 females. The TSH RI were obtained by Hoffmann method: the whole population, 0.59-5.59 μIU/ml (1 μIU/ml=1 mIU/L), male, 0.53-5.16 μIU/ml, female, 0.59-6.11 μIU/ml. The upper limits of TSH RI were higher with age and in winter (January): 18-30 years old, 0.62-5.57 μIU/ml, 71-80 years old, 0.49-6.45 μIU/ml; January, 0.59-6.40 μIU/ml, August, 0.60-5.56 μIU/ml; The RI of TSH by Bhattacharya method: the whole population, 0.58-5.80 μIU/ml, male, 0.55-5.02 μIU/ml, female, 0.62-6.21 μIU/ml. The upper limits of TSH RI were also higher with age and in winter (January): 18-30 years old, 0.65-5.67 μIU/ml, 71-80 years old, 0.46-5.99 μIU/ml, January: 0.61-6.52 μIU/ml, August: 0.61-5.69 μIU/ml. Compared to RI from reagent instruction, the differences of TSH RI from two indirect methods of total population, selected population, physical examination population were acceptable.Conclusions:TSH RI was established by indirect method. With the increase of age and winter, the upper limit of TSH reference interval tends to increase.
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Objective To prepare the trueness verification materials of C-reactive protein (CRP) and evaluate its homogeneity, stability and commutability. Methods The high and low CRP concentrations trueness verification materials were from patient leftover sera which were pooled, mixed thoroughly, filtered and aliquoted. The homogeneity, stability and commutability of these materials were evaluated according to CNAS(China National Accreditation Service for Conformity Assessment, CNAS)-GL29:2010 "Reference materials-General and statistical principles for certification (ISO Guide35:2006)"and the Clinical and Laboratory Standards Institute (CLSI) EP30A. The trueness verification materials were used to evaluate the commutability in 10 clinical CRP detection systems, using forty-five patients' leftover sera with different CRP concentration evaluated by Deming regression in EP30A of CLSI. Meanwhile, the commutability of dilution series of ERM DA-474/IFCC were evaluated using the same method. Results A total of two CRP concentration level trueness verification materials were prepared, with high and low concentration levels of 754 and 743 vials, 1 ml each, respectively. The preparation showed good homogeneity (F<F0.05(14,30);On the condition of room temperature, 2-8 ℃ and -80 ℃, these materials were stable for 7 days and 44 months respectively, the slope of the linear equation of | b1 | less than t0.95,n-2 · s(b1), there was no statistically significant difference between the slope and zero, the stability is satisfied. The materials and the dilution series of ERM-DA 474/IFCC also showed good commutability among patient sera in 10 systems. Conclusions The trueness verification materials of C-reactive protein (CRP) showed good homogeneity, stability and commutability. The dilution series ERM DA-474/IFCC also have good commutability. These provided experimental support for the value transfer and application of the trueness verification materials .
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Objective To explore the CRP harmonization by calibration using commutable trueness verification materials. Methods High and low level of CRP concentrations trueness verification materials(H and L) were prepared by Beijing center for clinical laboratories. Thesetrueness verification materials were diluted to 5 calibration points(5L, 4L+1H, 3L+2H, 1L+4H, 5H) by weighing method, respectively. These 5 points were used to calibrate four different brands of CRP detection system (Diasys, Leadman, Siemens and Roche) instead of the original procedure. Sera from 21 patients and the international standard ERM DA-474/IFCC were used to compare harmonization and trueness after calibration. Each sample above was measured twice. Results After calibration, the median of CV was reduced from 19.33％ to 2.92％ among 21 patient samples, less than the optimal CV based on biological variability (CV=10.6％). Compared with Desai, the slopes were closer to 1 from 0.90-1.09 to 0.93-0.96 after calibration. Meanwhile, if ERM-DA474/IFCC was used as the trueness verification materials, the absolute bias wasreduced from 3.08-11.07 mg/L to 0.52-2.97 mg/L which was close to theuncertainty of itself (2.5 mg/L). Conclusions Afterthe calibration which contained five linear concentration points of CRP trueness verification materials by weighing method, both harmonization and trueness of CRP were improved.
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Objective To value C-reactive protein ( CRP ) trueness verification materials and to perform the CRP trueness verification program in Beijing .Methods The CRP value of trueness verification materials were assigned by the international reference material ERM DA-474/IFCC, using 10 clinical routine detection systems at departments of clinical laboratory of Beijing Chaoyang and Luhe Hospital Affiliated to Capital Medical University .The calibration curves with 4 ERM DA-474/IFCC dilutions were established and used for value transfer for trueness verification materials of two levels .The uncertainty was also assessed during the process.Then, the trueness verification was performed in the EQA at Beijing Center for Clinical Laboratories ( BCCL ) among 42 clinical laboratories.The samples were distributed according to BCCL standard operating procedure .The Microsoft Excel 2007 and SPSS 17.0 were used to process the results and the function of efficiency ( En) was calculated to verify the difference between the value and the overall mean of all participating laboratories .Results The values and uncertainties of two trueness verification materials of CRP were (109.9 ±9.4) mg/L and (27.1 ±2.4) mg/L respectively.The results of trial application of two level trueness verification materials in the EQA at Beijing Center for Clinical Laboratories (BCCL) were satisfied.There were no significant difference between the transfer values from our study and the values from means of all laboratories in Beijing .The function of efficiency ( En ) was less than 1.Conclusions The valueswhich were established by using multiple detection platforms for CRP trueness verification materialswere accurate and the uncertainties were small .This method is a preferably method for CRP value assignment because there was no suitable reference method for CRP measurement till now .Thematerialswere suitable for the trueness verification program for clinical laboratories in Beijing .
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Objective To establish the target measurement uncertainty(MU)of the routine coagulation assay according to the External Quality Assessment data(EQA)of routine coagulation assay. Methods Beijing Center for Clinical Laboratory(BCCL)established the target measurementuncertainty for routine coagulation assayswith the"up-down"methodon the basis of 93 clinical laboratoriesEQA datain BeijingThese assays includedActivated partial thromboplastine time(APTT), Fibrinogen(FBG), International Normalized Ratio(INR), Prothrombin time(PT), Thrombin time(TT)and D-dimer, Compared with CLIA′88,the proficiency of current coagulation assayswas observed.Results The MU of six routine coagulation assayscompared with CLIA ′88 showed that: The 90th percentile MU met the creteriain APTTof group B,FBG of group A&B&C,INR of group B and D-dimer of group B.The 75th percentile MU met the creteriainINR of group A&C,PT of group C.The medium met the creteriainAPTT of group A&C,PT of group A and INR of group D.Conclusions Target Measurement Uncertainty was establishedin routine coagulation assay by using EQA data only,whichcan simplify the procedure of determining MU and continuously update MU according to the frequency of EQA.It has good clinical practical value.However, the applicability of this method should also be considered.
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Objective To investigate the internal quality control ( IQC ) on clinical chemistry , clinical immunology and clinical hematology in mutual recognition laboratories in medical institutions in Beijing.Methods By means of questionnaire survey and on -site investigation, fresh frozen serum and whole blood samples with assigned values by reference method were measured to investigate the status of IQC on clinical chemistry , clinical immunology and clinical hematology in 142 mutual recognition laboratories in medical institutions of Beijing,and results were analyzed.Results 142 copies of questionnaireson clinical chemistry, clinical immunology and clinical hematology were send out and 120, 97, and 101 laboratories returned the questionnaires respectively .The information feedback rate was 84.5%, 68.3% and 71.1%respectively .All the questionnaires were effective .Questionnaires survey results showed that more than 50%laboratories set up quality control goals and the most of the goals were probability for error detection ( Ped) 95%, probability for false rejection(Pfr)5%;About 70% laboratories usecd the same quality control plan for different tests ;The most frequently used quality control rules are 12s/13s/22s.On-site investigation showed that ,take the results of clinical chemistry for example , based on the desirable biological variation and WS/T 403 -2012 , most of the tests can't meet the quality control goalsunder the existing quality controlcondition.Conclusion Clinical laboratories should consider their actual situations , assess their own qualitylevels that they can reach , set reasonable quality standards for themselves , and make appropriateindividualized quality control plan.
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Objective To prepare the frozen human serum pools for AFP reference materials through quantity value transmission from several analysis systems . Methods Method establishment. According to the requirement of preparation for the national standard materials , the studies of homogeneity and stability of frozen human serum pools for AFP reference materials were carried out .The commutability of prepared AFP reference materials and WHO AFP 72/225 reference material were assessed .By use of four automated chemiluminescence analysis systems , the prepared reference materials and different dilutions of WHO reference material 72/225 were tested in the same run.The values of prepared AFP reference materials were assigned by comparing these results and the uncertainty was evaluated .Results The three levels of AFP reference materials were tested to be homogeneous .The long term stability had been observed at -80℃for 14 months.The different dilutions of WHO AFP 72/225 reference material and three levels of prepared reference materials were commutable with patient serum samples among the four analysis systems .Through multiple system quantity value transmission and total uncertainty evaluation , the assigned values ( IU/ml) of three levels of AFP reference materials were 23.0 ±3.0, 93.2 ±7.2, ( 26.1 ±2.4 ) ×102 respectively.Conclusions The three levels of AFP reference materials were homogeneous and stable in accordance with requirement of preparation for national standard materials .The assigned values were reliable.The materials showed accepted commutability across 4 analytical systems.These materials had been approved as the national certified reference materials .These reference materials could be applied for the calibration or calibration verification of clinical analytical systems and the external quality assessment schemes for clinical laboratories.
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Objective Through statistical analysis of specimen rejection reasons, aimed at finding the ways to reduce the failed specimen, making sure of continuous improvements in laboratory quality. Methods Department of Laboratory, Beijing ChaoYang Hospital, Capital Medical University had analyzed rejections specimen from October 2013 to September 2014 in CAP Q-TRACKS QT3 ( QT3: Laboratory Specimen Acceptability ) , and compared the laboratory rejection reasons with all laboratories of CAP. Results From October 2013 to September 2014, the total number of rejection specimen number was 2 367, in which 225 were incomplete labeled specimen/inadequate filled-out form, accounting for 9.5%.898 samples were rejected because of specimen clotted, accounting for 37.9%.The samples could not meet the requirement of specimen quantity of 254, accounting for 10.7%.Other reasons accounting for above 1%included wrong collection container, specimen hemolysis, lipemia or icteric specimen.After comparing the first five rejection reasons, Department of Laboratory, Beijing ChaoYang Hospital was found to be different with others laboratories of CAP.Conclusion The quality of the specimen is very important for the accuracy and reliability of the test results, and doing some positive statistical analysis and taking corrective measures can effectively reduce the unqualified specimen of the proportion.