Proficiency Testing Program Research Articles

Interlaboratory Comparison for Analysis of Histamine in Fish as Per ISO/IEC 17043:2010 and ISO 13528:2015

Histamine is a significant food quality, safety, and trade issue in the fisheries sector. In the absence of adequate proficiency testing for histamine in India, it was important to organize a proficiency testing (PT) program among 22 food analytical laboratories for the external assessment of proficiency of the laboratories following ISO 17043:2010 and ISO 13528:2015. The test item (fish) prepared was sufficiently homogenous and stable for the entire duration of the PT program. The Grubbs test employed on the data showed the absence of any outlier result in the present testing scheme. The assigned value of 45.31 mg kg-1 was determined using the ‘consensus approach’ with a standard uncertainty of 1.33 mg kg-1. The robust standard deviation value was 5.02 mg kg-1. The z score for the participant results varied from -1.96 to +1.47, implying that the analytical performance of the participant laboratories was in agreement with the criteria mentioned in ISO 17043:2010. The HorRat value of 1.13, lay between the acceptable range of 0.5-2.0. The distribution of the results as depicted by the kernel density plot revealed a fairly normal distribution of the participants. All the participant laboratories were able to satisfy the proficiency testing requirements, as implied by the z score- -1.96 to +1.47. Further, proficiency testing can be carried out at various analyte levels and other matrices of commercial importance to allow for effective quality assurance.

Assignment of a Reference Value Independent from the Participants and Its Implications Regarding Performance Evaluation in Proficiency Testing on the Determination of Raw Milk Freezing Point

Milk adulteration may cause losses or quality problems in the dairy industry, with implications regarding consumers’ health. The addition of water is one of the most common adulterations, which can be detected by determining the freezing point of milk. A proficiency testing (PT) program is in place in Chile concerning the determination of the freezing point of raw milk. A limited number of laboratories participate regularly to assure the validity of their measurements. The reference values were obtained independently through a calibration test, as recommended by ISO 13528:2022 in those cases where a small number of participants are evaluated. The uncertainty of the reference values assigned to nine PT rounds that included three PT items was investigated. A modification has been proposed for their calculations, which consists of the incorporation of the CRM uncertainty. This involves assessing the participants’ performance using the z’-score across all laboratories utilizing the thermistor method, which presents a slightly higher likelihood of inaccurate evaluation (2.9% of total participations). The assigned values demonstrated compatibility with the participants’ results. It is recommended that the same standard deviation for proficiency assessment be utilized for evaluating the performance of participants.

Evaluating the accuracy of multiple rapid diagnostic tests for HIV detection in serum samples analysed during point-of-care proficiency testing assessments.

HIV rapid diagnostic tests are crucial for timely diagnosis, especially in resource-limited settings. The World Health Organization recommends sensitivity ≥99 % and specificity ≥98 %. This study assessed RDT performance across South Africa's provinces using a proficiency testing program. From April to June 2023, 25,458 blinded serum samples were sent to testing facilities for screening and confirmatory testing. Sensitivity, specificity, predictive values, and concordance (Cohen's Kappa) were evaluated. The response rate was 98.25 %. Sensitivity and specificity were both 98.7 %, with agreement at 98.7 % (kappa 0.97, p < 0.001). Northern Cape showed the lowest sensitivity (91.8 %) and specificity (92.0 %), while Gauteng, KwaZulu-Natal, and Mpumalanga exceeded 99 %. Although national RDT performance met WHO standards, Northern Cape's results reveal the need for improved training, quality assurance, and proficiency testing to strengthen diagnostic accuracy.

An 18-Year Review of Hemoglobinopathy Proficiency Testing: Recommendations From the College of American Pathologists Hematology and Clinical Microscopy Committee.

The College of American Pathologists Hematology and Clinical Microscopy Committee implemented a hemoglobinopathy proficiency testing and education program to monitor and assess the performance of participating laboratories. To evaluate the performance of clinical laboratories for hemoglobinopathy proficiency testing from 2005 to 2023. The hemoglobinopathy challenges are composed of clinical case summaries and electrophoretic and chromatographic gel and tracing images. The participants are asked to determine (1) what hemoglobin chain is affected and (2) the hemoglobinopathy diagnosis. A total of 365 to 676 laboratories were enrolled in the proficiency testing program each year. Overall, the error rates for determination of the affected globin chain and a hemoglobinopathy diagnosis ranged from 0.6% to 56.5% and 0.5% to 86.5%, respectively. Twenty-three of 66 surveyed hemoglobinopathies (34.8%) had an error rate exceeding the consensus threshold of 20%. The globin gene detection error rate of the compound hemoglobinopathies was significantly higher when compared with just the α (P = .01) and β (P = .003) gene disorders. However, the error rate for the overall compound α/β-globin interpretation, although high at 23%, was not statistically significant when compared with just the α- or β-globin chain disorders. In repeat testing of the variants, there was no consistent improvement in performance. The program participants demonstrated variable performance with one-third of the surveys exceeding the 20% error rate. The error rate for compound hemoglobinopathies was even higher. Our data illustrate a critical need for continuing educational efforts with an algorithmic approach to hemoglobin disorders.

A rapid method for the determination of methylmercury and inorganic mercury species in whole blood by liquid chromatography with detection using vapor generation ICP-MS/MS.

Speciation methods provide a more detailed picture regarding human exposure to toxic metals/metalloids and their effects on human health. The toxicity of methylmercury (MeHg) differs considerably from inorganic mercury (iHg), such that their separation and quantification in whole blood is helpful in identifying sources and possible pathways of exposure. Liquid chromatography (LC) has several advantages over gas chromatography (GC) for the separation of iHg from MeHg due to the former's compatibility with uptake rates of common nebulizer systems used with ICP-MS and the latter's requirement for a derivatization step to produce gaseous Hg species for an effective separation. Here we report an improved method that was developed to separate and quantify MeHg and iHg species in whole blood using isocratic LC elution with determination by vapor generation (VG) coupled with ICP-MS/MS. Chromatographic separation of MeHg and iHg is achieved in ∼4 minutes on a C8 reversed phase column. In those rare cases where there may be human exposure to ethylmercury (EtHg), or where a certified reference material (CRM) is known to contain EtHg (e.g., NIST SRM 955c), all three Hg species can be separated by extending the LC elution time to 8 minutes. Adding VG post column boosts the signal-to-noise ratio, and lowers the LOD. With optimized sample preparation, the LC-VG-ICP-MS/MS method LOD for both iHg and MeHg is 0.2 μg L-1. Method validation was conducted using NIST SRM 955c Toxic Metals in Caprine Blood and NIST SRM 955d Toxic Elements and Metabolites in Frozen Human Blood. Additional validation data were generated using archived blood reference materials from multiple Proficiency Testing programs and External Quality Assessment schemes. Blood-based quality control materials, previously analyzed for Hg species using isotope dilution with GC coupled to ICP-MS, were provided by the US CDC.

Conventional Cytogenetic Analysis of Solid Tumor Abnormalities: A 25-Year Review of Proficiency Test Results from the College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee.

Background: The joint College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee works to ensure the competency and proficiency of clinical cytogenetic testing laboratories through proficiency testing (PT) programs for various clinical tests offered by such laboratories, including the evaluation of cytogenetic abnormalities in solid tumors. Methods: Review and analyze 25 years (1999-2023) of solid tumor chromosome analysis PT results, utilizing G-banded karyograms. A retrospective review of results from 1999 to 2023 was performed, identifying the challenges addressing solid tumors. The chromosomal abnormalities and overall performance were evaluated. Results: A total of 21 solid tumor challenges were administered during the period 1999-2018. No solid tumor challenges were administered during the period 2019-2023. Challenges consisted of metaphase images and accompanying clinical history for the evaluation of numerical and/or structural abnormalities. All 21 cases reached 80% grading consensus for abnormality recognition. However, five cases (24%) failed to reach consensus for nomenclature reporting by participating laboratories. These cases illustrate errors in reporting chromosomal abnormalities, including whole-arm translocations and those involving sex chromosomes. In addition, they highlight the challenges with differentiation of terminal and interstitial deletions, difficulties in identifying correct breakpoints, and omission of brackets in neoplastic cases. Conclusions: This comprehensive 25-year review demonstrates the exceptional proficiency of cytogenetic laboratories in accurately identifying chromosome abnormalities in solid tumors, while also highlighting the challenges of reporting specific types of chromosomal abnormalities.

Evaluation of various mass spectrometry mode based on gas chromatography for quantifying the polycyclic aromatic hydrocarbon metabolites in human urine

Hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) are frequently used as biomarkers to assess human exposure to polycyclic aromatic hydrocarbons (PAHs), which are typically present in minute concentrations in the human body. Although several studies have outlined methods for measuring OH-PAHs in human urine, these approaches may have limitations concerning the range of compounds detected, the sample volume required for pre-treatment, accuracy, and instrument maintenance costs. Advances in mass spectrometry technology have facilitated the use of various mass spectrometry modes based on gas chromatography. It is essential to evaluate different mass spectrometry modes to identify a more reliable and practical method for quantifying OH-PAHs in urine. Our comparative analysis of three gas chromatography-mass spectrometry modes revealed that advanced electron ionization (AEI) mode exhibited greater sensitivity for determination compared to electron ionization (EI) mode in tandem mass spectrometry. The method validation criteria were satisfied by GC-AEI-MS/MS, which demonstrated acceptable measurement errors (MEs) ranging from -23.0 % to 19.5 %, recoveries between 81.6 % and 112.1 %, and precision levels below 10.1 %. Furthermore, the reliability and accuracy of the GC-AEI-MS/MS method were corroborated through Intraclass Correlation Coefficient (ICC) evaluation (values > 0.75), participation in external proficiency testing programs (G-EQUAS), and analysis of certified reference materials, which exhibited a relative deviation of <6.1 %. In summary, GC-AEI-MS/MS is a robust and reliable method for analyzing urine samples and conducting large-scale human biological monitoring. It was employed to determine 16 OH-PAHs in human urine as part of the China National Human Biomonitoring Program (CNHBM).

Ensuring Quality and Consistency in OPC-53 Cement Testing: A Comprehensive Proficiency Testing Evaluation

The proficiency testing (PT) program is a critical part of quality assurance in laboratories, especially within industries like construction where cement testing is essential. This study provides a comprehensive evaluation of the fifth PT scheme for Ordinary Portland Cement (OPC) grade 53, conducted by the Nodal Laboratory. The key parameters assessed in this program were standard consistency, compressive strength, and soundness using the Le-Chatelier method. Twenty-four laboratories participated, and their performance was analyzed using advanced statistical methods, adhering to ISO 17043:2010 and ISO 13528:2015 standards. The results showed that most laboratories performed satisfactorily, with only one outlier identified in the soundness test. This paper covers all aspects of the PT program, from sample preparation to the distribution of materials, as well as the homogeneity and stability tests conducted on the samples. Statistical evaluation was carried out using Z-scores, which allowed the laboratories to be ranked according to their performance in each parameter. This method highlights discrepancies and provides a clear framework for participating laboratories to improve their testing procedures. Proficiency testing is essential for maintaining high standards in laboratory performance. It helps standardize testing methods across multiple laboratories, ensuring that OPC-53 cement meets strict quality and performance specifications. The program enables laboratories to identify performance gaps and take corrective actions, ensuring the reliability and accuracy of results. Participation in PT programs is a step toward continuous improvement, keeping laboratories aligned with international standards, ultimately benefiting the broader construction industry by ensuring the structural integrity of buildings and infrastructure. This study underscores the importance of regular PT participation. It not only provides a benchmark for laboratory performance but also ensures compliance with ISO standards. This fosters the consistent quality of cement used in large-scale construction, reducing the risk of structural failures and contributing to long-term safety and durability. The findings demonstrate the positive impact of PT programs on overall testing accuracy and laboratory reliability, emphasizing their role in advancing best practices in the construction industry.

Decreased variability in the site-specific results during participation in the External Quality Assurance Program Oversight Laboratory (EQAPOL) proficiency program for IFN-gamma enzyme-linked immunospot (IFN-γ ELISpot) assay

The NIAID DAIDS-sponsored External Quality Assurance Program Oversight Laboratory (EQAPOL) manages an interferon-gamma (IFN-γ) enzyme-linked immunospot (ELISpot) external proficiency program. The ELISpot program evaluates the accuracy and variability of results across laboratories. The variability in the program is quantified via the dispersion, which is the ratio of the variance over the mean of the background-corrected spot-forming cells (SFC) replicates obtained under stimulation with different peptide pools (CMV, CEF). This report includes the longitudinal analysis of the ELISpot program cohort composed of 22 laboratories from 2011 to 2022 to assess whether the within-lab variability has improved over time. Random intercept models of the dispersion over time showed a significant decrease in overall dispersion from an average of approximately 1.8 in 2011 to approximately 1.25 in 2022. Out of the 21 sites, 16 sites (4 being statistically significant) had a negative trend for dispersion over time. Our finding of a reduction of overall within-lab variability demonstrates the need for and benefit of proficiency testing programs.

A-280 The Good, the Bad, and the Downright Inappropriate reporting of Gram Positive Resistance Genes in a Proficiency Testing Program

Abstract Background Molecular technologies can rapidly identify the pathogen, allowing for the correct antimicrobial agent to be used for initial treatment. Many laboratories have implemented molecular technologies to identify the causative agents of infections from various bodily sources. Screening for potential resistance genes to common antimicrobial agents provides high value to clinicians to help guide optimal antimicrobial therapy selection. CLIA ‘88 required proficiency testing for physician office laboratories in 1994. This was in addition to the requirement for hospital and reference laboratories instituted under CLIA ‘67. This study compares the accuracy of laboratory performance for molecular multiplex platforms in the detection of Gram positive resistance genes from gold standard qualified samples in a novel proficiency program. Methods American Proficiency Institute, an independent proficiency testing provider, reviewed the reporting of various molecular multiplex systems against simulated patient samples in proficiency samples offered in 2023. Participants were instructed to only report resistance genes their systems were capable of testing for, and ensure they were appropriate for the organism recovered. Failure rates for participants were evaluated against an 80% participant consensus standard for detection of resistance genes. Results During the 2023 proficiency year, Gram positive targets were included 14 times in 4 different multiplex programs. Accuracy for correct reporting of resistance genes appropriate for the organism recovered ranged between 71.0%- 100%. Conversely, the number of laboratories reporting resistance genes that were inappropriate for the organism recovered ranged between 2.0% - 67.0%. Conclusions Based on the results reported by participants in API’s proficiency event, Molecular Multiplex platforms are accurately identifying Gram positive resistance genes. However, many participants using both FDA approved and LDT systems reported results for resistance genes that were not applicable for the organism recovered. This inaccurate reporting could potentially lead to inappropriate antimicrobial therapies being prescribed.

Proficiency testing within Eurotransplant.

Eurotransplant is responsible for the international allocation of organs between eight countries in Europe. All HLA laboratories affiliated to Eurotransplant must be EFI or ASHI-accredited and must participate in the Eurotransplant external proficiency testing (EPT) program, organized by the Eurotransplant Reference Laboratory (ETRL). EPT within Eurotransplant has a long tradition, starting in 1978. The current EPT program consists of the following schemes: HLA typing including serology, CDC crossmatching, HLA-specific antibody detection, and identification. Participants enter the results of laboratory tests using a web-based application. Assessed results are visible on the website. An additional component called "patient-based cases" runs since 2016. Results are summarized and published on the EPT website. Furthermore, these results are discussed during the annual extramural tissue typers meeting, which is organized by the ETRL. Thanks to this EPT program, the performance of all HLA laboratories affiliated to Eurotransplant can be monitored and corrected, if necessary. Because all affiliated laboratories are assessed in the same EPT program, where these laboratories show to be consistent in most of their results, Eurotransplant EPT has proven to be an efficient tool to create a more uniform level of quality of histocompatibility testing within Eurotransplant.

Harmonisation of the HLA tests for the diagnosis of coeliac disease: experiences from the Czech external proficiency testing program.

Coeliac disease (CD) is an autoimmune disorder caused by the ingestion of gluten-containing grains. One of the prerequisites for the development of the disease is the presence of specific combinations of HLA alleles at the DQA1 and DQB1 loci. The HLA test is a supportive diagnostic test. In the Czech Republic, approximately 3,500 HLA tests for CD diagnosis are performed annually in almost three dozen laboratories. The HLA Department of the Institute of Haematology and Blood Transfusion in Prague has been offering the EPT "Detection of HLA Alleles Associated with Diseases" for more than 10years. The results are evaluated in terms of the correct determination of predisposing alleles/allelic groups and clinical interpretation. Every year, we notice some problems with the detection of CD-associated alleles and the interpretation of results. Annual workshops are part of this EPT, and they also include recommendations for the interpretation of results. This interpretation is evolving based on the current knowledge in the field. The current recommendation for interpretation was adopted in 2023, dividing HLA-DQA1/DQB1 genotypes into three categories: 1) detected HLA genotype is associated with predisposition to coeliac disease; 2) coeliac disease could not be excluded based on the detected HLA genotype; 3) coeliac disease could be excluded with high probability based on the detected HLA genotype. The quality of examination is increasing but still needs improvement. Correct results and accurate interpretation can inform clinicians' decisions about the diagnosis of coeliac disease in appropriate patients.

High Prevalence of Multistep Algorithms in Diagnostic Clostridioides difficile Laboratory Testing.

Laboratory testing practices for diagnosis of Clostridioides difficile infection (CDI) have evolved in response to published guidelines, availability of highly sensitive nucleic acid amplification tests (NAATs), perceived problems with the specificity of NAATs, and CDI reporting requirements. To assess the current state of laboratory practice for diagnostic CDI testing. An optional 8-item supplemental questionnaire was distributed in December 2019 to the 1374 laboratories participating in the College of American Pathologists C difficile Detection (CDF) proficiency testing program challenge CDF-C. Of 1374 CDF-C participants, 1160 (84.4%) responded, predominantly representing laboratories based in the United States (1077 of 1160; 92.8%). The majority reported using a multistep testing algorithm (684 of 1159; 59.0%). Initial testing with a glutamate dehydrogenase and toxin A/B combination test followed by NAAT for discrepant results was the most common testing method (360 of 1146; 31.4%). NAAT alone (299 of 1146; 26.1%) was next, then NAAT followed by an assay that included toxin A/B enzyme immunoassay if NAAT is positive (258 of 1146; 22.5%). Only 5.4% (62 of 1146) reported using toxin A/B immunoassay alone. Most respondents (1093 of 1131; 96.6%) reported rejecting CDI tests on formed stool, but rejection of CDI testing in pediatric patients was uncommon (211 of 1131; 18.7%). Rejection of CDI testing in patients using laxatives was reported more often by US-based respondents (379 of 1054 [36.0%] versus 9 of 77 [11.7%], P < .001). Multistep algorithms for CDI diagnosis are widely used in line with published recommendations. Most respondents reported rejection of formed stool for CDI testing, but few reported rejection of testing in infants and patients taking laxatives, suggesting these may be areas of opportunity for laboratories to pursue in improving CDI testing practices.

Current laboratory testing practices for mismatch repair deficiency and microsatellite instability testing: A survey-based review of current laboratory practices.

To describe mismatch repair (MMR) and microsatellite instability (MSI) testing practices in laboratories using the College of American Pathologists (CAP) MSI/MMR proficiency testing programs prior to the 2022 publication of the MSI/MMR practice guidelines copublished by CAP and the Association of Molecular Pathology (AMP). Data from supplemental questionnaires provided with the 2020-B MSI/MMR programs to 542 laboratories across different practice settings were reviewed. Questionnaires contained 21 questions regarding the type of testing performed, specimen/tumor types used for testing, and clinical practices for checkpoint blockade therapy. Domestic laboratories test for MSI/MMR more often than international laboratories (P = .04) and academic hospitals/medical centers test more frequently than nonhospital sites/clinics (P = .03). The most commonly used testing modality is immunohistochemistry, followed by polymerase chain reaction, then next-generation sequencing. Most laboratories (72.6%; 347/478) reported awareness of the use of immune checkpoint inhibitor therapy for patients with high MSI or MMR-deficient results. The results demonstrate the state of MMR and MSI testing in laboratories prior to the publication of the CAP/AMP best practice guidelines, highlighting differences between various laboratory types. The findings indicate the importance of consensus guidelines and provide a baseline for comparison after their implementation.

Building Quality Control for Molecular Assays in the Global Measles and Rubella Laboratory Network.

More than 100 laboratories in the World Health Organization Global Measles and Rubella Laboratory Network (GMRLN) perform nucleic acid-based methods for case confirmation of measles or rubella infections and/or strain surveillance (genotyping). The quality of laboratory data is critical to ensure that diagnostic results and country reports to regional verification committees are based on accurate data. A molecular External Quality Assurance (mEQA) program was initiated by the US-CDC in 2014 to evaluate the performance of laboratories in the network. The inclusion of testing for measles and rubella viruses, with a focus on detection and genotyping, plus the diversity of assays and platforms employed required a flexible and comprehensive proficiency testing program. A stepwise introduction of new evaluation criteria gradually increased the stringency of the proficiency testing program, while giving laboratories time to implement the required changes. The mEQA program plays an important role in many processes in the GMRLN, including informing plans for the training of laboratory staff, access to reagents, and the submission of sequence data to global databases. The EQA program for Local Public Health Institutes in Japan is described as an example for national mEQA programs. As more laboratories initiate molecular testing, the mEQA will need to continue to expand and to adapt to the changing landscape for molecular testing.

CDC's Laboratory Activities to Support Newborn Screening for Spinal Muscular Atrophy.

Spinal muscular atrophy (SMA) was added to the HHS Secretary's Recommended Uniform Screening Panel for newborn screening (NBS) in 2018, enabling early diagnosis and treatment of impacted infants to prevent irreversible motor neuron damage. In anticipation of supporting SMA newborn screening, scientists at the U.S. Centers for Disease Control and Prevention (CDC) have worked towards building resources for public health laboratories in four phases since 2013. In Phase 1, CDC established a real-time PCR assay, which uses a locked nucleic acid probe to attain the needed specificity, to detect SMN1 exon 7. In Phase 2, we developed quality assurance dried blood spot materials made with transduced lymphoblast cell lines established from de-identified SMA patients, carriers, and unaffected donors. In 2021, CDC implemented Phase 3, a proficiency testing program, that now supports 115 NBS labs around the world. We are currently completing Phase 4, which includes the implementation of an external SMA quality control material program. Also, during this time, CDC has provided individual technical assistance to NBS programs and bench training to NBS scientists during our annual molecular workshop. These CDC-led activities have contributed to the rapid and full implementation of SMA screening in all 50 U.S. states as of February 2024.

The development and implementation of a proficiency testing program for SARS-CoV-2 using dried tube specimens in resource-limited countries

IntroductionWhen COVID-19 hit the world in 2019, an enhanced focus on diagnostic testing for SARS-CoV-2 was essential for a successful pandemic response. Testing laboratories stretched their capabilities for the new coronavirus by adopting different test methods. The necessity of having external quality assurance (EQA) mechanisms was even more critical due to this rapid expansion. However, there was a lack of experience in providing the necessary SARS-CoV-2 EQA materials, especially in locations with constrained resources.ObjectiveWe aimed to create a PT (Proficiency testing) programme based on the Dried Tube Specimens (DTS) method that would be a practical option for molecular based SARS-CoV-2 EQA in Low- and Middle-Income Countries.MethodsBased on previous ISO/IEC 17043:2010 accreditation experiences and with assistance from the US Centers for Disease Control and Prevention, The Supranational Reference Laboratory of Uganda (adapted the DTS sample preparation method and completed a pilot EQA program between 2020 and 2021. Stability and panel validation testing was conducted on the designed materials before shipping to pilot participants in six African countries. Participants received a panel containing five SARS-CoV-2 DTS samples, transported at ambient conditions. Results submitted by participants were compared to validation results. Participants were graded as satisfactory (≥ 80%) or unsatisfactory (< 80%) and performance reports disseminated.ResultsOur SARS-CoV-2 stability experiments showed that SARS-CoV-2 RNA was stable (-15 to -25 °C, 4 to 8 °C, (18 to 28 °C) room temperature and 35 to 38 °C) as well as DTS panels (4 to 8 °C, 18 to 28 °C, 35 to 38 °C and 45 °C) for a period of 4 weeks. The SARS-CoV-2 DTS panels were successfully piloted in 35 test sites from Zambia, Malawi, Mozambique, Nigeria, and Seychelles. The pilot results of the participants showed good accuracy, with an average of 86% (30/35) concordance with the original SARS CoV-2 expectations.ConclusionThe SARS-CoV-2 DTS PT panel is reliable, stable at ambient temperature, simple to prepare and requires minimal resources.

THC Content on a Dry Weight Basis: Implications for Hemp Legality.

The 2018 Farm Bill defines hemp as Cannabis sativa L. with a tetrahydrocannabinol (THC) concentration not more than 0.3% on a dry weight basis where THC is implied to be total THC (THCTotal) including both acid (Δ9-THCA) and neutral (Δ9-THC) forms. Effect of temperature and mass were studied to determine the quickest time to prepare fresh hemp suitable for grinding without affecting THCTotal. Proficiency testing program data were also analyzed to compare THCTotal contents on a dry versus wet weight basis. Fresh hemp of 150 and 400 g were freeze-dried or heat-treated at 50 °C, 60 °C, and 70 °C for various lengths of time up to 72 hours. Ground hemp was analyzed for moisture content via AOAC 934.01 and THCTotal via liquid chromatography/mass spectrometer (LC/MS) or gas chromatography with flame ionization detection (GC/FID). A data set analyzed from a proficiency testing program included moisture and THCTotal from 20 to 67 laboratories on 12 analytical samples circulated from 2020 through 2022. The quickest drying time of 24 h occurred at 70 °C with 150 g. These conditions did not affect THCTotal content on a dry weight basis. Twelve proficiency testing program analytical samples ranged from 5.8 to 11.4% moisture and 0.144 to 0.399% THCTotal on a wet weight basis. An increase in reported THCTotal on a dry weight basis compared to a wet weight basis ranged from 0.002 to 0.027% with a significant difference occurring in only one analytical sample. Suitable condition for drying hemp without altering THCTotal content was 24 h at 70 °C. Determining residual moisture in oven-dried ground hemp to calculate THCTotal content on a dry weight basis provides no benefit given minimal difference between contents on dry versus wet weight bases, interlaboratory variability, and terpene volatilization.

Experience of a proficiency testing program developed in Latin America for chemical analysis of coffee

Based on ISO 17043:2010, eight (8) proficiency testing (PT) rounds were organized for moisture, ash, caffeine, and total sugar analyses using commercial ground roasted pure coffee and roasted coffee with sugar added as PT materials as part of the Interlaboratory Food Analysis Rounds Program (PRIDAA, by its acronym in Spanish). Twenty-five (25) laboratories from Latin America participated in these PT Rounds. Results were evaluated using statistical procedures based on ISO 13528: 2016. The Z/Z′-scores used to evaluate the performance of laboratories were computed using the standard deviation for PT (σp) defined based on fitness-for-purpose, while the assigned values (mean, median, or robust mean) were obtained from the consensus of PT participants’ results. For ash and caffeine, 89 % and 88 % of PT participants achieved a satisfactory performance (|Z/Z’|≤2), respectively, as average of the eight (8) rounds. Only 75 % achieved a ‘‘satisfactory’’ performance in the case of total sugars and 83 % in the case of moisture. For total sugar and caffeine, results obtained with methods other than HPLC were not comparable to the assigned value defined as the consensus of the HPLC results. Significant improvements in the methodology were applied to the PT when the ISO 17043:2010 accreditation was achieved in 2020.

Conventional Cytogenetic Analysis of Constitutional Abnormalities: A 20-Year Review of Proficiency Test Results From the College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee.

The joint College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee works to ensure competency and proficiency of clinical cytogenetics testing laboratories through proficiency testing programs for various clinical tests offered by such laboratories, including the evaluation of constitutional abnormalities. To review and analyze 20 years of constitutional chromosome analysis proficiency testing results (2003-2022), primarily utilizing G-banded karyograms. A retrospective review of results from 2003 through 2022 was performed, identifying challenges addressing constitutional disorders. The chromosomal abnormalities and overall performance were evaluated. A total of 184 cases from 161 proficiency testing challenges were administered from 2003 through 2022. Challenges consisted of metaphase images and accompanying clinical history for evaluation of numerical and/or structural abnormalities. Of the 184 cases, only 2 (1%) failed to reach an 80% grading consensus for recognition of the abnormality. Both cases illustrated the limitations of correctly characterizing some chromosomal abnormalities, including recombinant chromosomal abnormalities and isochromosome identification. In addition, 2 cases failed to reach a consensus for nomenclature reporting: 1 with an isochromosome and another with a duplication. This 20-year review illustrates the high rate of competency and proficiency of cytogenetic laboratories in the correct identification of constitutional chromosome abnormalities.