A model for managing quality control for a network of clinical chemistry instruments measuring the same analyte.

OBJECTIVES: Monitoring quality control for a laboratory or network with multiple instruments measuring the same analyte is challenging. We present a retrospective assessment of a method to detect medically significant out-of-control error conditions across a group of instruments measuring the same analyte. The purpose of the model was to ensure that results from any of several instruments measuring the same analytes in a laboratory or a network of laboratories provide comparable results and reduce patient risk. Limited literature has described how to manage QC in these very common situations. METHODS: Single Levey-Jennings control charts were designed using peer group target mean and control limits for five common clinical chemistry analytes in a network of eight analyzers in two different geographical sites. The QC rules used were 13s/22s/R4s, with the mean being a peer group mean derived from a large population of the same instrument and the same QC batch mean and a group CV. The peer group data used to set the target means and limits were from a quality assurance program supplied by the instrument supplier. Both statistical and clinical assessments of significance were used to evaluate QC failure. Instrument bias was continually monitored. RESULTS: It was demonstrated that the biases of each instrument were not statistically or clinically different compared to the peer group's average over six months from February 2023 until July 2023. Over this period, the error rate determined by the QC model was consistent with statistical expectations for the 13s/22s/R4s rule. There were no external quality assurance failures, and no detected error exceeded the TEa (medical impact). Thus, the combined statistical/clinical assessment reduced unnecessary recalibrations and the need to amend results. CONCLUSIONS: This paper describes the successful implementation of a quality control model for monitoring a network of instruments, measuring the same analytes and using externally provided quality control targets. The model continually assesses individual instrument bias and imprecision while ensuring all instruments in the network meet clinical goals for quality. The focus of this approach is on detecting medically significant out-of-control error conditions.

Quality standards and internal quality control practices in medical laboratories: an IFCC global survey of member societies.

OBJECTIVES: The trueness and precision of clinical laboratory results are ensured through total quality management systems (TQM), which primarily include internal quality control (IQC) practices. However, quality practices vary globally. To understand the current global state of IQC practice and IQC management in relation to TQM the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Task Force on Global Laboratory Quality (TF-GLQ) conducted a survey of IFCC member countries on IQC practices and management. METHODS: The survey included 16 questions regarding IQC and laboratory TQM practices and was distributed to IFCC full and affiliate member countries (n=110). A total of 46 (41.8 %) responses were received from all regions except North America. RESULTS: Of the responding countries, 78.3 % (n=36) had legislative regulations or accreditation requirements governing medical laboratory quality standards. However, implementation was not mandatory in 46.7 % (n=21) of responding countries. IQC practices varied considerably with 57.1 % (n=28) of respondents indicating that they run 2 levels of IQC, 66.7 % (n=24) indicating they run IQC every 24 h and 66.7 % (n=28) using assay manufacturer IQC material sources. Only 29.3 % (n=12) of respondents indicated that every medical laboratory in their country has written IQC policies and procedures. By contrast, 97.6 % (n=40) of responding countries indicated they take corrective action and result remediation in the event of IQC failure. CONCLUSIONS: The variability in TQM and IQC practices highlights the need for more formal programs and education to standardize and improve TQM in medical laboratories.

Temporal, age, and geographical variation in vaccine efficacy against infection by the Delta and Omicron variants in the community in France, December 2021 to March 2022.

OBJECTIVES: We aimed to quantify how the vaccine efficacy of BNT162b2, messenger RNA-1273, AD26.COV2-S, and ChAdOx1 nCoV-19 against detected infection by the SARS-CoV-2 Delta and Omicron variants varied by time since the last dose, vaccine scheme, age, and geographic areas. METHODS: We analyzed 3,261,749 community polymerase chain reaction tests conducted by private laboratories in France from December 2021 to March 2022 with a test-negative design comparing vaccinated to unvaccinated individuals. RESULTS: Efficacy against detected infection by Delta was 89% (95% confidence interval, 86-91%) at 2 weeks, down to 59% (56-61%) at 26 weeks and more after the second dose. Efficacy against Omicron was 48% (45-51%) at 2 weeks, down to 4% (2-5%) at 16 weeks after the second dose. A third dose temporarily restored efficacy. Efficacy against Omicron was lower in children and the elderly. Geographical variability in efficacy may reflect variability in the ratio of the number of contacts of vaccinated vs unvaccinated individuals. This ratio ranged from 0 to +50% across departments and correlated with the number of restaurants and bars per inhabitant (beta = 15.0 [0.75-29], P-value = 0.04), places that only vaccinated individuals could access in the study period. CONCLUSION: SARS-CoV-2 vaccines conferred low and transient protection against Omicron infection.

External quality assessment practices in medical laboratories: an IFCC global survey of member societies.

OBJECTIVES: Clinical laboratory results are required for critical medical decisions, underscoring the importance of quality results. As part of total quality management, external quality assessment (EQA) is a vital component to ensure laboratory accuracy. The goal of this survey was to evaluate the current status of global laboratory quality systems and assess the need for implementation, expansion, or harmonization of EQA programs (EQAP) for Clinical Chemistry and Laboratory Medicine. METHODS: The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Task Force on Global Laboratory Quality (TF-GLQ) conducted a survey of IFCC full and affiliate members (n=110) on laboratory quality practice. A total of 41 (37.3%) countries representing all IFCC regions except North America provided responses about EQA availability and practices. RESULTS: All 41 countries perform EQA, 38 reported that their laboratories had EQA policies and procedures, and 39 further act/evaluate unacceptable EQA results. 39 countries indicated they have international and/or national EQAP and 30 use alternative performance assessments. EQA frequency varied among countries. Generally, an EQAP provided the EQA materials (40/41) with four countries indicating that they did not have an EQAP in their country. CONCLUSIONS: Globally, most laboratories participate in an EQAP and have defined quality procedures for EQA. There remain gaps in EQA material availability and implementation of EQA as a part of a total laboratory quality system. This survey highlights the need for education, training, and harmonization and will guide efforts of the IFCC TF-GLQ in identifying areas for enhancing global laboratory quality practices.

Dynamics of viral shedding during ancestral or Omicron BA.1 SARS-CoV-2 infection and enhancement of pre-existing immunity during breakthrough infections.

Omicron variant is circulating in the presence of a globally acquired immunity unlike the ancestral SARS-CoV-2 isolate. Herein, we investigated the normalized viral load dynamics and viral culture status in 44 fully vaccinated healthcare workers (HCWs) infected with the Omicron BA.1 variant. Viral load dynamics of 38 unvaccinated HCWs infected with the 20A variant during the first pandemic wave was also studied. We then explored the impact of Omicron infection on pre-existing immunity assessing anti-RBD IgG levels, neutralizing antibody titres against 19A, Delta and Omicron isolates, as well as IFN-γ release following cell stimulation with SARS-CoV-2 peptides. We reported that two weeks after diagnosis a greater proportion of HCWs infected with 20A (78.9%, 15/19) than with Omicron BA.1 (44.7%, 17/38; p = 0.02) were still positive by RT-qPCR. We found that Omicron breakthrough infections led to an overall enhancement of vaccine-induced humoral and cellular immunity as soon as a median [interquartile range] of 8 [7-9] days post symptom onset. Among samples with similar high viral loads, non-culturable samples exhibited higher neutralizing antibody titres and anti-RBD IgG levels than culturable samples. Additionally, Omicron infection led to an enhancement of antibodies neutralization capacity against other SARS-CoV-2 isolates. Taken together, the results suggest that Omicron BA.1 vaccine breakthrough infection is associated with a faster viral clearance than that of the ancestral SARS-CoV-2, in addition this new variant leads to a rapid enhancement of the humoral response against multiple SARS-CoV-2 variants, and of the cellular response.

Epidemiological and clinical insights from SARS-CoV-2 RT-PCR crossing threshold values, France, January to November 2020.

BackgroundThe COVID-19 pandemic has led to an unprecedented daily use of RT-PCR tests. These tests are interpreted qualitatively for diagnosis, and the relevance of the test result intensity, i.e. the number of quantification cycles (Cq), is debated because of strong potential biases.AimWe explored the possibility to use Cq values from SARS-CoV-2 screening tests to better understand the spread of an epidemic and to better understand the biology of the infection.MethodsWe used linear regression models to analyse a large database of 793,479 Cq values from tests performed on more than 2 million samples between 21 January and 30 November 2020, i.e. the first two pandemic waves. We performed time series analysis using autoregressive integrated moving average (ARIMA) models to estimate whether Cq data information improves short-term predictions of epidemiological dynamics.ResultsAlthough we found that the Cq values varied depending on the testing laboratory or the assay used, we detected strong significant trends associated with patient age, number of days after symptoms onset or the state of the epidemic (the temporal reproduction number) at the time of the test. Furthermore, knowing the quartiles of the Cq distribution greatly reduced the error in predicting the temporal reproduction number of the COVID-19 epidemic.ConclusionOur results suggest that Cq values of screening tests performed in the general population generate testable hypotheses and help improve short-term predictions for epidemic surveillance.

Characterisation of vaccine breakthrough infections of SARS-CoV-2 Delta and Alpha variants and within-host viral load dynamics in the community, France, June to July 2021.

We compared PCR results from SARS-CoV-2-positive patients tested in the community in France from 14 June to 30 July 2021. In asymptomatic individuals, Cq values were significantly higher in fully vaccinated than non-fully vaccinated individuals (effect size: 1.7; 95% CI: 1-2.3; p < 10-6). In symptomatic individuals and controlling for time since symptoms, the difference vanished (p = 0.26). Infections with the Delta variant had lower Cq values at symptom onset than with Alpha (effect size: -3.32; 95% CI: -4.38 to -2.25; p < 10-6).

[Retrospective analysis of the performance of the SARS-CoV-2 rapid antigen detection test compared to the reference RT-PCR test]. / Analyse rétrospective des performances du test de détection rapide antigénique du SARS-CoV-2 comparé au test de référence RT-PCR.

BACKGROUND: Discovered in 2019 in the region of Wuhan, China, the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) rapidly established itself as a major pathogenic agent of morbidity and mortality. France has implemented a strategy to fight this virus which relies essentially on widespread RT-PCR virological testing in order to isolate positive patients. Antigenic tests have recently been made available to help the diagnostics. We have conducted a retrospective study to determine the sensitivity of these antigenic tests, comparing them to the reference RT-PCR method. METHOD: Between December 7, 2020 and January 31, 2021, each patient we received in our laboratories for an RT-PCR test was enrolled. Out of 271,649 patients, 4,881 had been submitted to an antigenic test (TDR) in the preceding 24 hours. Comparing the data resulting from both tests, we established the sensitivity and the specificity of the antigenic tests. For our analysis we included the parameter of symptom and/or the value of Cycles threshold (Ct) in our parameters. RESULTS: The sensitivity of the TDRs compared to all the positive RT-PCR tests is 56%. We further demonstrate the correlation between the symptom duration and the reduction of the nasopharyngeal viral load. Based on this data, we have established that the sensitivity of the TDRs decreases very rapidly after symptom onset, contrary to the estimated viral load in the RT-PCR. Indeed, less the 24 hours after clinical symptom onset, the sensitivity of the TDRs decreases from 74% to 60%. By including the Ct value in our parameters, we have established that, despite a high viral load and clinical symptoms since 7 days or less, the sensitivity of the TDRs is 66%. Although, a high number of asymptomatic patients among carriers of SARS-CoV-2, we have estimated a specificity of 93% for our test. CONCLUSIONS: Performance in terms of sensitivity and specificity of the TDR, as assessed in practice, are inferior to those given by the manufacturer, which raises several questions. What is the impact of falsely negative results for patients carrying a high viral load? Are the implemented measures sufficient to prevent the epidemic?

Recommendations for the application and follow-up of quality controls in medical laboratories.

This is a translation of the paper "Recommendations for the application and follow-up of quality controls in medical biology laboratories" published in French in the journal Annales de Biologie Clinique (Recommandations pour la mise en place et le suivi des contrôles de qualité dans les laboratoires de biologie médicale. Ann Biol Clin (Paris). 2019;77:577-97.). The recommendations proposed in this document are the result of work conducted jointly by the Network of Accredited Medical Laboratories (LABAC), the French Society of Medical Biology (SFBC) and the Federation of Associations for External Quality Assessment (FAEEQ). The different steps of the implementation of quality controls, based on a risk analysis, are described. The changes of reagent or internal quality control (IQC) materials batches, the action to be taken in case of non-conform IQC results, the choice of external quality assessment (EQA) scheme and interpretation of their results as well as the new issue of analyses performed on several automatic systems available in the same laboratory are discussed. Finally, the concept of measurement uncertainty, the robustness of the methods as well as the specificities of near-patient testing and rapid tests are described. These recommendations cannot apply for all cases we can find in medical laboratories. The implementation of an objective alternative strategy, supported with documented evidence, might be equally considered.

[Recommendations for the application and the follow-up of quality controls in medical biology laboratories]. / Recommandations pour la mise en place et le suivi des contrôles de qualité dans les laboratoires de biologie médicale.

The recommendations that we formulate in this document come from LABAC, SFBC and FAEEQ. They describe the different steps from the initial application of quality controls, based on risk analysis: the changes of reagent batches or internal quality controls (IQC) batches, the course when IQC are not in accordance with references, the choice of external quality evaluation and the interpretation of its results, the comparability of results obtained in several analysers used in the same laboratory. Lastly, measurement uncertainty, robustness of methods and specificities of near-patient biology and rapid tests are described. Note that these recommendations cannot develop all cases that we could find in laboratories. It remains necessary to carry out an objective strategy, supported with documentary evidences.

[Do liquid wastes from automated instruments in medical laboratories have their proper microbicide effect?] / Les rejets liquides des automates de biologie médicale ont-ils un effet microbicide propre qui permettrait de s'affranchir de leur traitement pour risque infectieux ?

Liquid wastes from clinical biology automated systems are currently evacuated in the urban network after chemical treatment to eliminate a possible risk of infection. Since these wastes are ecotoxic because of the presence of numerous chemical reagents, we studied their intrinsic microbicidal power towards a selection of infectious agents widely found in clinical specimens. The objective was to determine if an additional anti-infectious treatment before elimination is necessary. Thus, we evaluated the bactericidal effect of liquid wastes of several automated systems towards four bacterial species (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis) and their virucidal activity against a non-enveloped virus, resistant in the environment (adenovirus). This effect was determined for different exposure times. Our results showed that the antibacterial activity was highly variable depending on the waste-bacteria pair considered (varying from no activity to complete sterilization of a strong bacterial inoculum). The liquid wastes were on the other hand globally inactive towards adenovirus.

[Proposed recommendations for the practical use of internal quality controls (IQC) in a medical biology laboratory]. / Propositions de recommandations pour l'utilisation pratique des contrôles internes de qualité (CIQ) dans un laboratoire de biologie médicale.

We propose a set of recommendations and practices to optimize the use of quality control of medical biology examinations. The fundamentals are reviewed: definition of a series of analysis, IQC at one or more level, Westgard alert rules and rejection, practical remedial actions to take for the technician, corrective and preventive actions to be implemented by the biologist. We have also formalized three flowcharts to guide the technician in their daily practice to ensure analytical quality of investigations carried out. These decision trees are the result of the experience submitted by an accredited and professional laboratory attentive to the ongoing improvement of IQC. This article can provide useful assistance to biologists for accreditation but also aims to foster collaboration reliable medical biology laboratory at the appropriate management of patients.