Development and evaluation of an external quality control and internal quality control containing real-time RT-PCR assay for the detection of o'nyong-nyong virus

O'nyong-nyong fever is a mosquito-borne tropical viral disease while few molecular diagnostic tools have been established for its surveillance until now. In the current study, a single-step, dual-color real-time reverse transcription polymerase chain reaction (RT-PCR) assay which contained both external quality control (EQC) and internal quality control (IQC) prepared by armored RNA technique was developed and evaluated for the detection of o'nyong-nyong virus (ONNV). Results showed that the assay was established successfully without cross-reaction with genetically related or symptom-alike diseases, which showed high specificity of the assay. The coefficient of variation of the assay was 0.97%, far less than 5%, indicating good repeatability of the assay. The lower limit of detection of the assay could reach as low as 100 copies of genome equivalent. During evaluation, the assay could correctly detect ONNV from spiked human serum samples and Anopheles species mosquito samples, while no ONNV positive was observed either from serum samples of patients with acute febrile illness or from local Anopheles species mosquitoes, suggesting no ONNV had been transmitted locally. In conclusion, the assay could potentially provide a valuable platform for ONNV molecular detection, which may improve the preparedness for future o'nyong-nyong fever outbreaks.

Development and clinical evaluation of an online automated quality control system for improving laboratory quality management

BACKGROUND

We developed an efficient online automated quality control (AUTO QC) system and tested its feasibility on automatic laboratory assembly lines.

METHODS

AUTO QC is based on developed quality control software (Smart QC) and designed adaptable consumables before. We applied the system to two assembly lines in our laboratory. Using third-party quality control samples, we evaluated the impact of the online AUTO QC system on out-of-control rate, biosecurity risk, turnaround time (TAT) and cost.

RESULTS

AUTO QC significantly decreased the occurrence rate of the Westgard quality control rules 1_3S/2_2S/R_4s and 1_2S, representing out-of-control and warning, respectively. The out-of-control rates were reduced by 58%, and the potential biosecurity risk of the samples decreased by 90%. The AUTO QC implementation also reduced the median TAT (by 7 min), the number of full-time employees and the cost of the quality control samples (by 45%).

CONCLUSIONS

The total laboratory AUTO QC system can improve the quality and stability of QC testing and reduce cost.

Practical Considerations for Clinical Laboratories in Top-down Approach for Assessing the Measurement Uncertainty of Clinical Chemistry Analytes

Background

The top-down (TD) approach using internal quality control (IQC) data is regarded a practical method for estimating measurement uncertainty (MU) in clinical laboratories. We estimated the MU of 14 clinical chemistry analytes using the TD approach and evaluated the effect of lot changes on the MU.

Methods

MU values were estimated using subgrouping by reagent lot changes or using the data as a whole, and both methods were compared. Reagent lot change was simulated using randomly generated data, and the mean values and MU for two IQC datasets (different QC material lots) were compared using statistical methods.

Results

All MU values calculated using subgrouping were lower than the total values; however, the average differences were minimal. The simulation showed that the greater the increase in the extent of the average shift, the larger the difference in MU. In IQC data comparison, the mean values and MU exhibited statistically significant differences for most analytes. The MU calculation methods gave rise to minimal differences, suggesting that IQC data in clinical laboratories show no significant shift. However, the simulation results demonstrated that notable differences in the MU can arise from significant variations in IQC results before and after a reagent lot change. Additionally, IQC material lots should be treated separately when IQC data are collected for MU estimation.

Conclusions

Lot changes in IQC data are a key factor affecting MU estimation and should not be overlooked during MU estimation.

A unique Levey-Jennings control chart used for internal quality control in human papillomavirus detection

OBJECTIVE

The purpose of this study was to provide an updated estimate of the prevalences of different types of human papillomavirus (HPV) in females in Chaoshan District and to establish an internal quality control (IQC) method for excluding false-positive results in HPV detection by using the Levey-Jennings control chart.

METHOD

HPV types were detected in 23,762 cervical samples by using PCR membrane hybridization. The means and standard deviations (SDs) of the positive rates were calculated, the Levey-Jennings chart was plotted, and the rules for "out of control" and "warning" were established. A set of standardized IQC for HPV DNA tests was developed based on the values and Levey-Jennings charts.

RESULT

In 466 batches, the positive rate exceeded the 1 + 2SD rule 24 times, but there was no consecutive exceedance, which was considered "in control". When the positive rate exceeded the 1 + 3SD rule 8 times with consecutive exceedance, it was considered "out of control". Further examination revealed that detections showing "out of control" had an undesirable random error, indicating that contamination may occur due to improper operation.

CONCLUSION

This unique Levey-Jennings control chart is a practical method for eliminating false-positive results in HPV DNA detection and should be widely applicable in molecular diagnostic laboratories.

[The establishment and multicenter application of internal quality control system for real-time quantitative PCR detection of BCR-ABL (P210) transcript level]

Objective: The study aims to establish a perfect BCR-ABL (P210) internal quality control system and ensure the long-term stability and comparability of the detection results between laboratories and to popularize and apply it in the three hospitals. Methods: The Qilu Hospital of Shandong University (H1) prepared a set of the BCR-ABL (P210) quality control substances to establish and improve internal quality control system. We went to other three participating hospitals (H2, H3, and H4) to inspect quality control before the measurement. In addition, we mailed 25 sets of quality control substances to each of the hospital for detection. The slope and intercept of the standard curve of each hospital and the detection results were analyzed and statistically judged using the Levey-Jennings quality control chart combined with the Westgard multirule theory. Then, we made a quality control evaluation. Results: ①An internal quality control system for the BCR-ABL (P210) transcript levels monitoring was successfully established for the quality inspection before the measurement, statistical judgment during the measurement, and evaluation after the measurement. ② Both the slope and intercept of the standard curve of the four hospitals was under control. ③The multicenter quality control substance judgment results were as follows: for H1 hospital, two times of "1(2s)" warning were found in the middle-level quality control substance, which was judged as being under control; for H2 hospital, one time of "1(2s)" warning was found for each quality control substance, which was judged as being "2(2s)" out of control; for H3 hospital, its high-level quality control substance violated the "1(3s)" rule, and low-level quality control substance appeared "1(2s)" warning, which was judged as "1(3s)" out of control; and all quality control substances were under control in H4 hospital. ④The quality control evaluation and correction were as follows: two hospitals were under control, and the other two hospitals had an "out of control." We found out the reason for the out of control and corrected them. ⑤The comparisons of the original values of the multicenter quality control substance were as follows: there were statistical differences in the results of high-level quality control substance among the four hospitals, and no significant difference was found in the results of the medium-level and low-level quality control substance. ⑥The comparisons of the IS values of the multicenter quality control substance were as follows: the IS values of the three quality control substance in H2 and H3 hospitals were significantly higher than those of H1 hospital, and H2 hospital was significantly higher than H3 hospital. Conclusion: A perfect and stable internal quality control system for the BCR-ABL (P210) transcripts has been established, which can effectively ensure the accuracy and stability of the clinical detection results. This internal quality control system has been successfully popularized and applied in other hospitals.

[Surveillance of Acaricides in Honey]

By using the LC-MS/MS method developed by us, we determined the residual amounts of acaricides in honey samples commercially available in Tokyo from April 2015 to March 2021. The results of analyzing 127 honey samples, amitraz was detected in 85 samples at the level of 1.1-34.1 μg/kg. Propargite was detected in 3 samples at 2.4-3.8 μg/kg. None of them was beyond the Japanese MRLs or uniform limits. In these survey for 6 years, amitraz was detected in high rate throughout the year. But, the present results imply that amitraz has been used properly in actual bee-keeping because of no violation of MRL and less fluctuation in the detected levels. On the other hand, propargite was detected at the levels over LOQ in domestic honey samples for the first time in 2020, which may suggest a new trend of acaricide use in apiculture in Japan.

Internal Quality Control Data of Urine Reagent Strip Tests and Derivation of Control Rules Based on Sigma Metrics

Background

Urine reagent strip test (URST) results are semi-quantitative; therefore, the precision of URSTs is evaluated as the proportion of categorical results from repeated measurements of a sample that are concordant with an expected result. However, URSTs have quantitative readout values before ordinal results challenging statistical monitoring for internal quality control (IQC) with control rules. This study aimed to determine the sigma metric of URSTs and derive appropriate control rules for IQC.

Methods

The URiSCAN Super Plus fully automated urine analyzer (YD Diagnostics, Yongin, Korea) was used for URSTs. Change in reflectance rate (change %R) data from IQC for URSTs performed between November 2018 and May 2020 were analyzed. Red blood cells, bilirubin, urobilinogen, ketones, protein, glucose, leukocytes, and pH were measured from 2-3 levels of control materials. The total allowable error (TE_a) for a grade was the difference in midpoints of a predefined change %R range between two adjacent grades. The sigma metric was calculated as TE_a/SD. Sigma metric-based control rules were determined with Westgard EZ Rules 3 software (Westgard QC, Madison, WI, USA).

Results

Seven out of the eight analytes had a sigma metric >4 in the control materials with a negative grade (-), which were closer to the cut-offs. Corresponding control rules ranged from 1_2.5s to 1_3.5s.

Conclusions

Although the URST is a semi-quantitative test, statistical IQC can be performed using the readout values. According to the sigma metric, control rules recommended for URST IQC in routine clinical practice are 1_2.5s to 1_3.5s.

Quality Control in the Slovenian National Colorectal Cancer Screening Program

OBJECTIVES

The objective of the study was to assess the impact of an internal quality indicator (QI) audit on the quality level of colonoscopies in the National Colorectal Cancer Screening Program (NCCSP).

DESIGN

Sixty-eight colonoscopists from 29 endoscopic centres participated in the NCCSP from April 2009 to January 2015. Controlled QIs were the percentage of total colonoscopies, adenoma detection rate (ADR), mean adenoma per procedure (MAP), mean adenoma per positive procedure (MAP+), right-sided ADR, sessile serrated lesion (SSL) detection rate, and patient responses to post-procedural questionnaires. A group of 3 expert endoscopists from the NCCSP Council performed 91 inspections and provided education.

RESULTS

A total of 891.364 (58.2%) Slovenian citizens participated in the first 3 screening rounds of the NCCSP. Among 46.552 (6%) positive individuals, 42.866 (92.1%) underwent first colonoscopies. Total colonoscopies were performed in 98% of endoscopies (p = 0.459 between cycles), mean ADR was 51.8% (p = 0.872 between cycles), mean percentage of adenoma in the right colon was 37.5% (p = 0.227 between cycles), mean MAP was 1.1 (p = 0.981 between cycles), mean MAP+ was 2.0 (p = 0.824 between cycles), and mean SSL detection rate was 3% (p < 0.001). We observed great difference in QIs between endoscopists and a significant increase in MAP, ADR in the right colon, and SSL per endoscopist during the 6-year period. Due to quality underperformance, 3 endoscopic centres (10.3%) and 13 endoscopists (19.1%) were excluded from the program.

CONCLUSIONS

The success of the NCCSP is related to the quality of colonoscopies performed. To ensure the proper quality level, regular audit and permanent education are needed.

[The influence of peripheral blood sample storage and delivery on the quantitative detection result of BCR-ABL (P210) transcript levels]

目的

探索慢性髓性白血病（CML）患者外周血样本的存储和运输对实时定量PCR（RQ-PCR）检测BCR-ABL（P210）转录本水平的影响。

方法

采集84例CML患者外周血样本，根据储存时间（0、6、12、24、48和72 h）、温度［室温（18～24 °C）和低温（2～8 °C）］以及振荡条件（振荡时长3、6和12 h）设置不同分组，RQ-PCR法检测不同条件下外周血样本BCR-ABL（P210）转录本水平。本研究将BCR-ABL拷贝数、ABL拷贝数和BCR-ABL（P210）转录本水平等原始数据进行对数转化（log₁₀^N）。

结果

①琼脂糖凝胶电泳结果显示：室温条件下，储存48、72 h的样本RNA出现显著降解；②储存温度方面，总体样本中，室温储存48、72 h的样本BCR-ABL拷贝数检测水平显著低于低温储存的样本（P<0.05）；然而BCR-ABL（P210）转录本水平在低温储存与室温储存条件下检测结果差异无统计学意义（P>0.05）；③储存时间方面，与基线的3.35±1.60相比，总体样本的BCR-ABL拷贝数检测结果仅在室温储存储存下48 h（2.93±1.59）和72 h（2.79±1.42）显著下降（P<0.05）；与基线的5.47±0.35相比，总体样本中ABL拷贝数检测结果在48 h（低温5.29±0.30，室温5.06±0.38）和72 h（低温5.11±0.54，室温4.64±0.79）均显著下降（P<0.05）。但是，与基线的−0.56±1.51相比，无论低温或室温条件下，不同储存时间（6、12、24、48和72 h）的样本BCR-ABL（P210）转录本水平检测结果无显著改变（P>0.05）；④振荡方面，与基线的−0.60±1.37相比，振荡3、6、12 h的样本BCR-ABL（P210）转录本水平检测结果无显著改变（P>0.05）。

结论

样本储存时间、储存温度及运输振荡因素可以影响BCR-ABL、ABL拷贝数的检测结果，但对BCR-ABL（P210）转录本水平定量检测结果无显著影响。

Examination of conditions for regular internal quality control in identification of microorganisms using MALDI-TOF MS

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was approved for medical use in 2011, and is currently used as a rapid, accurate and low-cost technique for bacterial identification. Microbiological testing and internal accuracy control in Japan are mainly implemented in accordance with the standards of the Clinical and Laboratory Standards Institute (CLSI). However, few facilities perform internal accuracy control of bacterial identification by MALDI-TOF MS. Therefore, we examined the procedures for internal accuracy control of bacterial identification using MALDI-TOF MS in daily work at clinical laboratories in the seven hospitals.

Moving Rate of Positive Patient Results as a Quality Control Tool for High-Sensitivity Cardiac Troponin T Assays

Background

A small shift in high-sensitivity cardiac troponin T (hs-cTnT) assays can lead to different result interpretation and consequent patient management. We explored whether a small bias could be detected using conventional internal quality control (QC) procedures, evaluated the performance of moving average (MA)-based QC procedures, and proposed a new QC procedure based on the moving rate (MR) of positive patient results of hs-cTnT assays.

Methods

The ability of conventional QC to detect a 5 ng/L bias was examined using the1_3s/ 2_2s/R_4s multi-rule procedure as deviation rules.We developed MA and MR procedures for the hs-cTnT assay using eight months of patient data. The performance of different MA or MR procedures was investigated by calculating the median number of patient samples affected until a bias introduced into the dataset was detected (MNPed). After comparing the MNPed across different procedures, we selected an optimal MA or MR procedure for validation. Validation graphs were plotted using the minimum, median, and maximum number of results affected until bias detection.

Results

Our conventional QC procedures could not detect a positive bias of 5 ng/L. When a positive bias was introduced, MNPed was much higher using MA than using MR, with cut-off values of 5 ng/L and 14 ng/L, respectively. MR validation charts for optimal procedures provided insight into the MR performance.

Conclusions

The MR procedure could detect different errors with few false alarms. In the hs-cTnT assay, the MR procedure with a smaller cut-off value outperformed MA and conventional QC procedures for small bias detection.

Precision of autoantibody assays in clinical diagnostic laboratories: What is the reality?

BACKGROUND

ISO 15189 accreditation remains a challenge for specialized laboratories. In the field of autoimmunity, beside the crucial problem of absence of standardization, laboratories have to manage the analytical performances of the large panel of assays in terms of sensitivity and specificity, but also on their measurement precision for which no reference values are available on biorepositories.

METHODS

As an initiative of the French EASI (European Autoimmunity Standardization Initiative) group, French clinical diagnostic laboratories were requested to participate in a survey aiming to analyze the coefficients of variation (CVs) of intra-run and inter-run variability obtained with assays quantifying 14 different autoantibodies. Two performance goals corresponding to the 90th percentile and the 50th percentile (lowest CV values reached by 90% and 50% of laboratories respectively) defined for three levels of concentration were calculated. The impact on the assay performances of the number of measurements, of the nature of the internal quality control (IQC) and the type of immunoassay, was also analyzed.

RESULTS

414 and 616 values of intra-run and inter-run CVs were collected, respectively. The 50th percentile performance goals were comprised between 1.0% and 8.9% for the intra-run CVs, and between 1.8% and 14.6% for the inter-run CVs. At 90th percentile, the performance goals were comprised between 3.2% and 13.5% for the intra-run CVs, and between 7.3% and 30.8% for the inter-run CVs. CVs calculated from 10 values were similar to those obtained from more values. Higher imprecision was observed when the antibody levels of the IQC was lower than 2 fold the positive threshold. Commercial IQCs gave lower CVs than IQCs derived from patient samples.

CONCLUSION

Our results allow proposing some acceptability limits for the precision performances of the autoantibody assays, compatible with the reality of life in diagnostic laboratories and clinical care.

Measurement Uncertainty Impacts Diagnosis of Diabetes Mellitus: Reliable Minimal Difference of Plasma Glucose Results

INTRODUCTION

The diagnosis of diabetes mellitus is based on suitable cut-off values of specific biomarkers, such as the concentration of glucose in plasma. The German Diabetes Association has very recently published a clinical practice guideline on the definition, classification and diagnosis of diabetes mellitus that recommends measurements of plasma glucose concentration have an imprecision defined as a minimal difference (MD) of at a fasting plasma glucose concentration of 7.0 mmol/L. To obtain reliable values for the MD, we investigated long-term and short-term measurement uncertainty.

METHODS

The imprecision was determined by two approaches: (1) a long-term dataset with imprecision based on the Guideline of the German Medical Association on Quality Assurance in Medical Laboratory Examinations (Rili-BAEK), in a medical laboratory operating 24/7, using internal quality control (IQC) data for four concentrations during a 10-year period; and (2) a detailed short-term dataset with imprecision assessed by hourly measurements of control materials. These datasets were used to calculate the MD cut-off (MD_cut-off) as: [Formula: see text]  = 2  [Formula: see text], where SD is the standard deviation and k = 2 represents a confidence level of 95%.

RESULTS

The MD_cut-off of ≤ 0.7 mmol/L at a fasting plasma glucose concentration of 7.0 mmol/L (MD_cut-off 7.0) for the long-term and the short-term approaches were 0.44 and 0.40 mmol/L, respectively. The MD_cut-off 7.0 from both approaches was therefore below the recommended value of 0.7 mmol/L. It was noted that the variability in performance within and between instruments can be covered by reporting the long-term MD_cut-off 7.0 across all connected instruments. In this study, stable results for the MD_cut-off 7.0 were obtained after 1 year.

CONCLUSION

Imprecision as measured by IQC data is remarkably stable over many years of operation. Current imprecision assessment usually focuses on only single instruments, whereas clinicians perceive the measurement as the result of the combined analytical performance of all instruments used for a certain assay. In the clinical setting, the MD may be a more useful measure of imprecision, and we suggest deriving the MD_cut-off combined from all instruments and control cycles that are used in the patient care setting for a given analyte.

Long-Term Quality Control Program Plan for Cord Blood Banks in Korea: A Pilot Study for Cryopreservation Stability

Background

Maintaining the quality of cryopreserved cord blood is crucial. In this pilot study, we describe the results of the internal quality control program for a cord blood bank thus far.

Methods

Donated cord blood units unsuitable for transplantation were selected for internal quality control once a month. One unit of cord blood, aliquoted into 21 capillaries, was cryopreserved and thawed annually to analyze the total nucleated cell count, CD34⁺ cell count, cell viability test, and colony-forming units assay.

Results

No significant differences in the variables (total nucleated cell count, cell viability, CD34⁺ cell count) were observed between samples cryopreserved for one and two years. Upon comparing the variables before cryopreservation and post thawing with the capillaries of one year of storage, cell viability and CD34⁺ cell counts decreased significantly. The use of cord blood samples in capillaries, which can be easily stored for a long period, was similar to the methods used for testing segments attached to the cord blood unit.

Conclusions

The results of this study may be useful for determining the period during which the quality of cryopreserved cord blood units used for transplantation is maintained.

[Inter-and intra-operator variability in the analysis of semen parameters: results from a quality control program]

Introduction

L’analyse du sperme est d’une importance majeure dans l’exploration de l'infertilité masculine. Afin de s’assurer de la fiabilité des résultats rendus, l’implantation du management de qualité en spermiologie est devenue une nécessité.Le but de ce travail a été d’évaluer la variabilité intra- et inter-opérateurau cours de l’analyse des paramètres spermatiques au sein de notre laboratoire de spermiologie, à travers la mise en place d’un programme de contrôle de qualité.

Méthodes

Quatre opérateurs ayant des niveaux d’expérience différents ont participé à l’étude. La variabilité inter-individuelle des résultats des lectures de la mobilité, la concentration et la morphologie spermatique a été évaluée sur plusieurs échantillons de sperme de qualités différentes. Pour chaque paramètre spermatique, la variabilité intra-individuelle a été évaluée en analysant les résultats des lectures de plusieurs aliquotes issus de chacun des échantillons utilisés.

Résultats

Les coefficients de variation moyens inter-opérateurs ont été de12.8%, 19.8% et 48.9% pour la mobilité, la concentration et la morphologie spermatique, respectivement. Les coefficients de variation moyens intra-opérateurs ont été de6.9%, 12.3%et 42.7% pour la mobilité, la concentration, et la morphologie spermatique, respectivement. Mis à part quelques écarts (erreurs aléatoires), la plupart des mesures réalisées ont été dans les limites d’acceptabilité pour l’ensemble des opérateurs.La variabilité de l’évaluation morphologique des spermatozoïdes a été particulièrement influencée par le niveau d’expérience de l’opérateur.

Conclusion

Les résultats de cette étude mettent l’accent sur la nécessité d’une formation adéquate du personnel de laboratoire, et de la participation régulière aux contrôles de qualité internes afin de minimiser les divergences et d’améliorer la fiabilité des résultats.

Comparison of markers of coagulation activation and thrombin generation test in uncomplicated pregnancies

INTRODUCTION

Pregnancy is a well-established risk factor for venous thromboembolism, and is associated with a state of hypercoagulability or parameters of thrombin generation. Currently, there is a lack of consensual data on thrombin generation during pregnancy. This study aimed to find a sensitive and specific biological marker of coagulation activation and to identify parameters of thrombin generation.

PATIENTS AND METHODS

The population included 101 women with uncomplicated pregnancies. The objective of this study was to correlate thrombin generation test (measured at 5pM tissue factor, 4μM lipids and without thrombomodulin), with fibrinogen and markers of blood coagulation activation: D-dimer, prothrombin fragments 1+2 (F1+2), thrombin-antithrombin complexes (TAT) and fibrin monomer complexes (FMC) in these women. Internal quality control was performed in each set of experiments.

RESULTS

Fibrinogen, D-dimer, F1+2, and TAT concentrations increased significantly throughout pregnancy, and were correlated with term of pregnancy. In our study, thrombin generation seemed to increase early on, and then remained stable throughout normal pregnancy, in contrast with other markers of blood coagulation activation, excepting FMC. The latter are subject to large inter-individual variations, especially during second trimester. No correlation was demonstrated between thrombin generation parameters and other activation markers.

CONCLUSION

While markers of coagulation activation significantly increased during pregnancy, thrombin generation increased only early on and remains stable during pregnancy. Finding a sensitive and specific biological marker for vascular pregnancy complications, such as FMC and thrombin generation levels, requires further investigation.

Quality in diagnostic microbiology: experiential note to emphasize value of internal control programs

Background:

Quality control (QC) in diagnostic microbiology is a matter of effective, efficient, accurate reporting in the expected turnaround time. Major stages of the analytical “standard operational procedures” where QC could be easily affected include organism identification and antibacterial susceptibility testing.

Aim:

The objective of this experiential technical note is to provide an evidence base to highlight the value of internal QC program in evaluating the effectiveness and efficiency of a laboratory's standard operational procedures; and the competences of individual scientific/technical staff.

Materials and Methods:

This report is based on four different scenarios requiring internal QC, including cases that are not reported within the turnaround time of standard operational procedures. Small-scale evaluations of (i) internal QC program, (ii) ciprofloxacin vs. moxifloxacin susceptibilities, and (iii) calibrated dichotomous susceptibility vs. directed susceptibility testing were performed.

Results:

The internal QC program identified sources of discrepancies in laboratory results. Evidence base for decision on new methodology and antibiotic testing were developed. For instance, it is observed that calibrated dichotomous susceptibility gives greater annular radius than directed susceptibility (P < 0.01).

Conclusions:

Internal QC program continues to be valuable means of identifying discrepancies, and vetting new ideas. This report presents evidence base to reaffirm that the need for internal QC is ever present.