The role of EQA in harmonization in laboratory medicine - a global effort

Exploration of suitable external quality assessment materials for serum C-peptide measurement

OBJECTIVES

To find suitable external quality assessment (EQA) materials for serum C-peptide, we evaluated the commutability of five types of processed materials.

METHODS

Seventy-four individual serum samples and 12 processed samples including three EQA samples currently in use, frozen human serum pools (FHSP), and three other kinds of processed samples were prepared by dissolving WHO International Standard Reagent for C-peptide (WHO ISR 13/146) in three different matrixes: 0.05 % bovine serum albumin, fetal bovine serum and human serum pools. Samples were analyzed using the isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method and six widely used immunoassays. The commutabilities of processed materials were assessed according to the difference in bias approach recommended by the IFCC. And the short- and long-term stability of FHSP samples at different temperatures were also evaluated.

RESULTS

Out of the five kinds of processed materials, FHSP samples were commutable on most assays. In contrast, the EQA materials currently in use were only commutable on a few immunoassays. Additionally, processed materials derived from WHO ISR 13/146 were found to be un-commutable on over half of immunoassays. The FHSP samples could be stably stored at 4 and -20 °C for at least 16 days, and at -80 °C for at least 1 year, but at room temperature only for 12 h.

CONCLUSIONS

With clarified commutability and stability information, the human serum pool samples along with the developed ID-LC-MS/MS method could be used in the EQA program to promote the comparability among laboratories for C-peptide measurement in China.

A mathematical algorithm to harmonize measurements for thyroid-stimulating hormone between instruments

BACKGROUND

Thyroid-stimulating hormone (TSH) is measured differently between diagnostic units using different devices, which makes cross-comparisons challenging. Here, we have developed a mathematical algorithm to harmonize TSH measurements between 2 instruments, the Abbott ISR2000 and the Siemens ADVIA Centaur XP.

METHODS

Applying the principle of the maximum allowable error between the standard curve and real signal values, the minimum number of comparison samples required for TSH hormone detection was calculated for both instruments. Next, a mathematical algorithm describing the relationship between TSH standard curves from both instruments was established. The algorithm was then tested on sample measurements from both instruments, with signals transformed to Siemens ADVIA Centuar XP-type data. Finally, test results were assessed where the relative error was 

RESULTS

Before conversion, the mean percentage error between the TSH results of samples measured on both instruments was 23.20% (>1/2 TEa). After algorithmic transformation, the average percentage error was reduced to 7.93% (<1/2 TEa).

CONCLUSIONS

Our algorithm enables TSH measurements across different instruments to be comparable, and provides a method to harmonize TSH data between laboratories that utilize different instrumentation.

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Key Words

• Comparability
• Conversion
• Determination
• Mathematical algorithm
• Thyroid-stimulating hormone (TSH)

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MESH Headings

• Humans
• Thyrotropin
• Algorithms

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Affiliation(s)

Xin Zhou Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu 610041, China; Jintang First People's Hospital, Chengdu 610400, China
Zaishuan Liu Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu 610041, China
Yining Ma College of Mathematics of Sichuan University, Chengdu 610065, China
Chongwei Zhang Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu 610041, China
Yongkang Wu Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu 610041, China; Jintang First People's Hospital, Chengdu 610400, China.

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Therapeutic drug monitoring status of four common antibiotics: vancomycin, meropenem, linezolid and teicoplanin

Accurate therapeutic drug monitoring (TDM) of vancomycin, meropenem, linezolid and teicoplanin are conducive to developing optimal therapeutic regimes for patients. However, the measurement status of those drugs in different laboratories has not been reported. In this study, four samples including two frozen plasma samples and two lyophilized plasma samples were measured by over 35 laboratories across China. The inter- and intra-laboratory %CV, biases (%) of laboratories and intra- and inter-measurement-system %CV were calculated and analyzed. The short-term stability and homogeneity of those drugs in samples were studied. The results of frozen and lyophilized samples were also compared to determine whether there were significant differences in their matrix effects on various measurement systems. Results showed most laboratories' intra-laboratory %CVs were less than 9% for all drugs, and the mean inter-laboratory %CVs were 18.4%, 86.4%, 19.1% and 37.1% for vancomycin, meropenem, linezolid and teicoplanin measurements, respectively. For vancomycin, the intra-measurement %CV of commercial measurement systems was found to be smaller than that of other measurement systems. For meropenem, linezolid and teicoplanin, the agreement among laboratories using self-developed methods (Liquid chromatography-mass spectrometry [LC-MS] or high-performance liquid chromatography [HPLC]) was not satisfactory as most intra-measurement system CVs% were over 20%. Drugs in lyophilized samples were found to be more stable than in frozen samples, and no obvious differences in matrix effects were found for those two kinds of processed samples on most measurement systems. In conclusion, this study depicted the measurement status of those drugs in clinical laboratories, and found the lyophilized samples were more suitable EQA material for those drugs.

Pathologists Overseas: A volunteer-based model for building sustainable, high-quality pathology and laboratory medicine services in low- and middle-income countries

For thirty years Pathologists Overseas (PO) has worked in low- and middle-income countries (LMICs) to provide affordable, sustainable, and high-quality pathology and laboratory medicine (PALM) services through strategic partnerships and the efforts of our large volunteer network. We address low quality diagnostic services by targeting the 3 pillars of PALM quality: human resources, systems, and quality and accreditation. To improve human resource capacity, PO and our partnering organizations provide virtual continuing education to pathologists and laboratory professionals in these countries. To improve systems, we provide laboratory information system installation and implementation support. Lastly, to improve quality and help laboratories progress toward accreditation, we support an external quality assurance program for laboratories in LMICs. As a relatively small organization, PO demonstrates that a network of dedicated volunteers, in partnership with corporations and professional organizations, can initiate sustainable change in the quality of PALM services in LMICs by focusing efforts on the core components of laboratory quality.

Integrating quality control and external quality assurance

Effective management of clinical laboratories relies upon an understanding of Quality Control and External Quality Assurance principles. These processes, when applied effectively, reduce patient risk and drive quality improvement. In this Review, we will describe the purpose of QC and EQA and their role in identifying analytical and process error. The two concepts are linked, and we will illustrate that linkage. Some EQA providers offer far more than analytical surveillance. They facilitate training and education and extend quality improvement and identify areas where there is potential for patient harm into the pre-and post-analytical phases of the total testing process.

EQA/PT scheme to improve the equivalence of enzymatic results between mutual recognition laboratories in Beijing

Background

To utilize the external quality assessment (EQA)/proficiency testing (PT) scheme to evaluate the equivalence of different clinical enzymatic measuring systems in Beijing.

Methods

The Beijing Center for Clinical Laboratory (BCCL) distributed three investigation samples to mutual recognition clinical laboratories in Beijing including alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ‐glutamyltransferase (GGT), creatine kinase (CK), and lactate dehydrogenase (LDH). These samples were derived from serum pools with values assigned by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) enzymatic reference measurement procedures (RMPs). Each laboratory performed duplicate tests of the samples. Then, the samples at level 1 were used to recalibrate individual measuring systems for repeating the tests. BCCL collected data for evaluation of their analytical quality.

Results

Before recalibration, the biases of ALT and AST tests were not traceable to the IFCC RMPs, and the bias pass rates of GGT, CK, and LDH tests were only 51.2%, 55.7%, and 48.6% respectively. After recalibration, the pass rates of ALT, AST, GGT, CK, and LDH increased to 95.1%, 82.9%, 95.1%, 97.1%, and 70.0% respectively. The EQA/PT also showed that after recalibration, more than 95% of laboratories met the optimum level specifications of the biological variation for ALT, AST, GGT, and CK tests and the desirable for LDH tests.

Conclusion

The enzymatic tests in Beijing need to be further standardized by category 1 or 2 EQA/PT scheme for mutual recognition between clinical laboratories. The criteria of biological variation are more relevant for determining the equivalence of clinical enzymatic tests.

External quality assessment program for biochemical assays of human seminal plasma: a French 6-years experience

BACKGROUND

In 1999, despite a longstanding use, the WHO manual for the examination of human semen finally proposed to assay several biochemical components of the seminal plasma for a functional exploration of the male accessory glands. At the same time, an international effort was made to standardize laboratory tests and to increase their performance through ISO 15189 accreditation. In this setting, participation to relevant external quality assessment (EQA) schemes is an essential requirement for laboratories. To fulfil this injunction, we have organized an EQA program for seminal biochemistry using presumed commutable samples. In this study, we aimed to report an overview of the French laboratory offer, the kinds of assays used, their performance as well as their likelihood of satisfying ISO15189 requirements for EQA.

RESULTS

Between 2014 and 2019, we performed seven surveys. A median of six laboratories participated to each survey giving a ratio of one laboratory per 11.2 million inhabitants. Seven biomarkers are routinely assayed but the core set shared by all laboratories comprised citrate and zinc (prostate), fructose (seminal vesicles) and α-1, 4 glucosidase (epididymis). The use of CE-IVD marked methods concerned between 0 to 75% of overall assays. According to analytical specifications, 100% of laboratories results were compliant for zinc, 75% for citrate and α-1,4 glucosidase and 67% for fructose. By combining overall data in an empirical scoring system, we identified several types of seminal biomarkers: citrate, fructose and zinc appear as good candidates for a full accreditation, α-1,4 glucosidase still presents an analytical weakness, but prostatic acid phosphatase, free L-carnitine and glycerophosphocholine cannot be accredited in the current state.

CONCLUSIONS

We organized the first French EQA program for seminal biochemistry to help local laboratories to face their legal requirement to be fully accredited by 2020. It could be improved still further but it gave us an oversight on the analytic landscape. Effective methods are available for a confident biochemical exploration of prostate and seminal vesicles. However, that of epididymis appeared unexpectedly fragile. This andrological issue should be addressed by dedicated recommendations from health authorities and scientific societies.

Assessors assemble: the need for harmonised external quality assessment schemes for emerging diagnostic methodologies in the field of parasitology

Global travel and migration trends have meant a huge increase in the numbers of people exposed to tropical parasitic diseases. Thus, there is an increasing need for robust, reproducible and reliable diagnostic techniques in the field. Advanced molecular and lateral flow techniques have pushed the boundaries of clinical parasite diagnostics with their enhanced sensitivities and specificities. These emerging technologies are, however, not without their challenges, and recently there has been multiple evidence of a lack of consensus among protocols and results obtained by quality assessment of these novel technologies. This commentary discusses findings from some recent quality assessment studies in the field of blood and faecal parasitology. The article also makes recommendations for a unified and harmonised approach towards delivering high-quality clinical parasitology diagnoses, especially through the use of proficiency testing.

Harmonising EQA schemes the next frontier: challenging the status quo

There is a focus on standardisation and harmonisation of laboratory results to reduce the risk of misinterpretation of patient results assayed in different laboratories. External quality assessment (EQA) is critical to assess the need for harmonisation and to monitor the success of procedures to achieve harmonisation. However, EQA providers are being stretched to meet the needs of their participants with proven commutable material with reference method targets, a range of clinically significant levels of the materials, detailed and customised data analysis, and educational support. The path ahead for harmonisation of EQA schemes will require leadership from an organisation that has the support and confidence of EQA providers, like the European Organisation for External Qualily Assurance Providers in Laboratory Medicine.

WHO malaria nucleic acid amplification test external quality assessment scheme: results of distribution programmes one to three

BACKGROUND

The World Health Organization (WHO) recommends parasite-based diagnosis of malaria. In recent years, there has been surge in the use of various kinds of nucleic-acid amplification based tests (NAATs) for detection and identification of Plasmodium spp. to support clinical care in high-resource settings and clinical and epidemiological research worldwide. However, these tests are not without challenges, including lack (or limited use) of standards and lack of reproducibility, due in part to variation in protocols amongst laboratories. Therefore, there is a need for rigorous quality control, including a robust external quality assessment (EQA) scheme targeted towards malaria NAATs. To this effect, the WHO Global Malaria Programme worked with the UK National External Quality Assessment Scheme (UK NEQAS) Parasitology and with technical experts to launch a global NAAT EQA scheme in January 2017.

METHODS

Panels of NAAT EQA specimens containing five major species of human-infecting Plasmodium at various parasite concentrations and negative samples were created in lyophilized blood (LB) and dried blood spot (DBS) formats. Two distributions per year were sent, containing five LB and five DBS specimens. Samples were tested and validated by six expert referee laboratories prior to distribution. Between 37 and 45 laboratories participated in each distribution and submitted results using the online submission portal of UK NEQAS. Participants were scored based on their laboratory's stated capacity to identify Plasmodium species, and individual laboratory reports were sent which included performance comparison with anonymized peers.

RESULTS

Analysis of the first three distributions revealed that the factors that most significantly affected performance were sample format (DBS vs LB), species and parasite density, while laboratory location and the reported methodology used (type of nucleic acid extraction, amplification, or DNA vs RNA target) did not significantly affect performance. Referee laboratories performed better than non-referee laboratories.

CONCLUSIONS

Globally, malaria NAAT assays now inform a range of clinical, epidemiological and research investigations. EQA schemes offer a way for laboratories to assess and improve their performance, which is critical to safeguarding the reliability of data and diagnoses especially in situations where various NAAT methodologies and protocols are in use.

Terminology, units and reporting - how harmonized do we need to be?

Harmonization initiatives in laboratory medicine seek to eliminate or reduce illogical variations in service to patients, clinicians and other healthcare professionals. Significant effort will be required to achieve consistent application of terminology, units and reporting across laboratory testing providers. Current variations in practice for nomenclature, reference intervals, flagging, units, standardization and traceability between analytical methods, and presentation of cumulative result data are inefficient and inconvenient, or worse yet, patient safety risks. All aspects of laboratory service across the "total testing process" ultimately depend on concise, reliable communication. Clinical terminologies (e.g. SNOMED-CT, LOINC, IFCC/IUPAC NPU) provide a mechanism to correctly identify an analyte or panel of tests within a request for testing and communicate the results back to the clinician or electronic health record (EHR). Electronic systems for requesting and reporting laboratory testing are said to be interoperable when reliable connection and communication of content occur. Modern electronic reports and EHRs will provide greater flexibility and functionality, but also require effective guidelines or standards to ensure consistent representation of laboratory data. Programs to harmonize service in these areas require ongoing local, national and international efforts and should incorporate stakeholders from laboratories, medical staff, information technology and informatics specialists, patient representatives and government. The process of identifying harmonized best practice, then ensuring uptake across many laboratory testing providers, is generally iterative rather than "one off". New opportunities for additional harmonization will be generated as analytical performance, standardization and traceability, and diagnosis and treatment continue to evolve.

A 3-year-long investigation of the authenticity of the return results of hepatitis B virus qualitative testing in external quality assessment in East China

BACKGROUND

In external quality assessments (EQAs), it is important and necessary for participants to return authentic test results. However, to obtain better evaluation results, some laboratories have lacked confidence that their own and have preferred to rely upon the test results in surrounding laboratories. These violations covered up errors during testing and affected the authenticity of the returned data. The occurrence of violations in EQA launched by different EQA organizers is still unknown because these violations were carried out in private. In this paper, we adjusted the hepatitis B virus (HBV) qualitative EQA schemes to uncover some of the violations by using specially designed sample combinations in four EQA surveys to show the authenticity and accuracy of HBV testing in some prefectures of East China.

METHODS

Four HBV qualitative EQA surveys were selected from 2016 to 2018, which were named 201602, 201701, 201702, and 201801, and a total of 474 laboratories were included. In the first two EQA surveys, the same EQA sample combinations were distributed. In the last two EQA surveys, three kinds of different sample combinations were designed and distributed with specific plans. The result of adding different sample combinations was that each laboratory only had a 33.3% chance of receiving the same sample combinations as those received by the surrounding laboratories. In addition, the laboratories were not aware that those samples with the same serial numbers might have different concentrations and target values. The sample concentrations, mode of delivery, requirements, results reports, and evaluation criteria were all the same as those of the first two EQA surveys.

RESULTS

The number of laboratories with failed tests increased from fourfold to sevenfold between the first two and the last two EQA surveys. The number of failed tests in 201702 was eight times that in 201701 during the same year. Six (6 of 469, 1.28%) and three (3 of 472, 0.64%) poor performer laboratories (PPLabs) appeared in 201602 and 201701, respectively, while the number of those laboratories increased to 29 (29 of 474, 6.12%) in 201702 and 201801. Failed tests from PPLabs accounted for 70.5% (201702) and 68.7% (201801) of the total failed tests. The increase in the number of PPLabs was not universal but was concentrated in some prefectures.

CONCLUSIONS

The current EQA results for HBV qualitative testing were not as good as originally anticipated. Violations during the EQA surveys caused by exchanging test results with other laboratories and by modifying results before returning still occurred in some prefectures of East China. The laboratories that were in violation can be partly exposed as PPLabs by providing different kinds of sample combinations. Through such an EQA adjustment, the laboratory would have to re-establish confidence in its own testing results from HBV EQA samples. Then, evaluations of HBV qualitative testing samples in EQA would be more authentic and accurate in East China.

External quality assessment programs in the context of ISO 15189 accreditation

Effective management of clinical laboratories participating in external quality assessment schemes (EQAS) is of fundamental importance in ensuring reliable analytical results. The International Standard ISO 15189:2012 requires participation in interlaboratory comparison [e.g. external quality assessment (EQA)] for all tests provided by an individual laboratory. If EQAS is not commercially available, alternative approaches should be identified, although clinical laboratories may find it challenging to choose the EQAS that comply with the international standards and approved guidelines. Great competence is therefore required, as well as knowledge of the characteristics and key elements affecting the reliability of an EQAS, and the analytical quality specifications stated in approved documents. Another skill of fundamental importance is the ability to identify an alternative approach when the available EQAS are inadequate or missing. Yet the choice of the right EQA program alone does not guarantee its effectiveness. In fact, the fundamental steps of analysis of the information provided in EQA reports and the ability to identify improvement actions to be undertaken call for the involvement of all laboratory staff playing a role in the specific activity. The aim of this paper was to describe the critical aspects that EQA providers and laboratory professionals should control in order to guarantee effective EQAS management and compliance with ISO 15189 accreditation requirements.

Maternal thyroid-stimulating hormone reference ranges for first trimester screening from 11 to 14 weeks of gestation

BACKGROUND

To establish maternal thyroid-stimulating hormone (TSH) reference ranges for first trimester screening from 11 + 0 to 13 + 6 weeks of gestation.

METHODS

A total of 10 592 singleton and 201 twin consecutive Caucasian pregnant women who underwent simultaneously prenatal first trimester Down's syndrome screening and thyroid function screening from January 2010 to November 2017 were included in the study. Women with positive antithyroid peroxidase antibody (TPOAb) and positive personal history of thyroid disease were previously excluded. TSH was measured by immunochemiluminescent assay on ci 16200 Abbott Architect analyzer. Nonparametric percentile method (also known as CLSI C28.A3) was used for the determination of reference ranges.

RESULTS

We established reference ranges of TSH for the period of gestation from 11 + 0 to 13 + 6 weeks of pregnancy as 0.16-3.43 mU/L for singleton Caucasian pregnancies and 0.02-2.95 mU/L for twin Caucasian pregnancies. The median (IQR) of TSH for singleton pregnancies was higher than that for twin pregnancies (1.25 mU/L (0.83-1.81) vs 0.84 (0.37-1.47), respectively; P < .0001).

CONCLUSIONS

Each first trimester screening center should be aware of which type of immunoassay their laboratory uses. TSH reference ranges in women during the first trimester of pregnancy are lower than those for general population. Twin pregnancies have lower TSH than singleton pregnancies.

The EFLM strategy for harmonization of the preanalytical phase

The Working Group for the Preanalytical Phase (WG-PRE) was officially established by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) in 2013, with the aim of improving harmonization in the preanalytical phase across European member societies. Since its early birth, the WG-PRE has already completed a number of projects, including harmonizing the definition of fasting status, patient and blood tubes identification, color coding of blood collection tubes, sequence of tubes during blood drawing and participation in the development of suitable preanalytical quality indicators. The WG-PRE has also provided guidance on local validation of blood collection tubes, has performed two European surveys on blood sampling procedures and has organized four European meetings to promote the importance of quality in the preanalytical phase. The future activities entail development and validation of an external quality assessment scheme focused on preanalytical variables, development and dissemination of a survey about the local management of unsuitable samples in clinical laboratories, as well as release of EFLM phlebotomy guidelines. This article summarizes all recent achievements of the WG-PRE and illustrates future projects to promote harmonization in the preanalytical phase.