Referee Laboratories Research Articles

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

BackgroundThe 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.MethodsPanels 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.ResultsAnalysis 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.ConclusionsGlobally, 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.

Twenty-year review of laboratory performance on enteric parasitology external quality assessment surveys 1992–2011, Ontario Canada

Quality Management Program–Laboratory Services (QMP–LS) is a mandatory external quality assessment (EQA) and accreditation programme for laboratories in Ontario. This report summarizes performance of Ontario laboratories on QMP–LS enteric parasitology EQA surveys and compares this performance over time. The results reported by participating laboratories were assessed against the expected results as determined by reference or referee laboratories. The number of laboratories licensed for parasitology decreased dramatically over the 20 years. On average, more than 80 % of participants and often more than 90 % were able to detect and identify the species and stages for the majority of parasites. Many of the challenges contained multiple parasites and about half contained low numbers, which affected performance on individual samples. The level of performance by Ontario laboratories on parasitology EQA surveys was consistently high over the 20 years. The parasites that presented the most difficulty were Enteromonas hominis and Trichomonas hominis.

A GUM-compliant uncertainty budget for the analysis of total carbon dioxide (TCO2) in equine plasma

Samples of plasma from chosen horses are collected prior to racing for the analysis of total carbon dioxide (TCO2). Five or six (dependent on jurisdiction) tubes of blood are taken as required for a screen, followed (if positive) by confirmation (two tubes in quadruplicate) and, further confirmation (two tubes in quadruplicate) at a second referee laboratory. The threshold limit prescribed by the rules of racing is an amount concentration of 36.0 mM, with further action ensuing if the reported concentration is greater than 37.2 mM. Using QC data and an analysis of the measurement procedure, the combined standard measurement uncertainty of a measurement result was estimated to be 0.22 mM. This leads to a conclusion that the odds of incorrectly deciding that a sample at the threshold limit exceeded the action concentration, are 13 000 000:1 against. The combined standard measurement uncertainty could be reduced to 0.20 mM by combining results from the first and referee laboratories. An allowance for uncertainty of measurement of 1.0 mM is proposed, which leads to odds of 185 000:1 against concluding a sample is over the threshold limit when, in fact, it is not.

Canines as sentinels for Lyme disease in San Diego County, California.

Prevalence of Lyme borreliosis in canine sentinels has been shown to correlate with infection in humans. One thousand canine sera (917 dogs, 83 coyotes) obtained from animal control authorities and area veterinarians were screened by ELISA for antibodies to Borrelia burgdorferi. Results were validated by Western blot and indirect fluorescent antibody (IFA) tests at referee laboratories. Criterion for a positive Western blot was presence of 5 of 10 of the most common antigen IgG bands; for IFA, >1:128 or the equivalent when correcting for interlaboratory variability. Twenty-two of 1,000 canines were confirmed serologically positive (21 dogs and 1 coyote; seroprevalence 2.3% and 1.2%, respectively). Lifestyle, breed size, gender, and age were not statistically predictive of seropositive status. No regional clustering of seropositive animals was detected. The low prevalence of seropositivity in sentinel canines suggests the Lyme borreliosis hazard in San Diego County is minimal.

Evaluation of Filter Paper Blood Lead Methods: Results of a Pilot Proficiency Testing Program

Lead testing on dried filter paper (FP) blood spots is used routinely by some laboratories for lead poisoning screening. Proficiency testing (PT) as required under CLIA '88 laboratory regulations has not been available for these methods. We describe a suitable PT scheme and evaluate FP laboratory performance based on program results. Monthly testing events consisting of five FP specimens were provided to six participating laboratories. Results were evaluated against target values determined by referee laboratories. Preliminary FP laboratory results showed poor agreement with specimen target values, exhibiting a mean absolute bias of 0.29 micromol/L (5.9 microg/dL). Five of six participating laboratories demonstrated significant improvement in later testing events, with bias decreasing to 0.12 micromol/L (2.5 microg/dL). Performance varied widely between the participating laboratories and appeared to be method dependent. When evaluated using CLIA blood lead acceptability criteria, the proportion of acceptable individual specimen results (n = 35) ranged from 54% to 100%. On a testing event basis (n = 7), the proportion of acceptable events ranged from 29% to 100%. A suitable FP PT program now exists to capably assist and monitor FP laboratories. Based on overt PT results, properly utilized FP testing methods can accurately measure blood lead concentration.

System to Monitor a Portion of the Total Testing Process in Medical Clinics and Laboratories: Evaluation of a Split-Specimen Design

To evaluate a split-specimen design to identify problems in the testing process in hospital and physician office laboratories, we examined the testing for serum total cholesterol (n = 646) and potassium (n = 732) at 11 medical clinics evaluating 30-199 patients (mean, 125). Clinic personnel collected three tubes of blood from each patient. One specimen was processed routinely, the second was sent to a referral laboratory (RL), and the third specimen was sent to a holding facility for storage. The corresponding stored sample was retrieved and divided into three audit samples randomly and when result difference for the first two specimens exceeded critical values; one audit sample was sent to the original participant, the second to the RL, and the third to a referee laboratory. When three criteria were used, the result discrepancy rates were 2.5-8.7% for potassium and 1.5-4.6% for cholesterol. The split-specimen design could be implemented and evaluated as a monitoring system for a portion of the testing process.

Determination of Acid-Detergent Fiber and Crude Protein in Forages by Near-Infrared Reflectance Spectroscopy: Collaborative Study

A collaborative study was conducted to determine the standard error of difference among laboratories for near-infrared reflectance spectroscopic (NIRS) determination of acid-detergent fiber (ADF) and crude protein in forages. The 6 participating laboratories were members of the USDA/ARS National Near-Infrared Reflectance Spectroscopy Forage Research Project. The NIRS calibration equations were developed in the Associate Referee's laboratory for crude protein and ADF and were transferred to the instrument in each of the other collaborating laboratories. The calibration set included over 650 diverse forage samples with crude protein and ADF calibration data; the validation set included 94 samples of bermudagrass. Among-laboratory reproducibility for the NIRS method, calculated as the relative standard deviation for reproducibility (RSDR), was 1.14% for ADF and 0.42% for crude protein. The variance component for among-laboratory variation (coefficient of variation) was 2.54% for ADF and 2.89% for crude protein. These results confirm that it is possible to calibrate, validate, and transfer (NIRS) equations and data among laboratories for the accurate determination of ADF and crude protein, and thereby demonstrate that NIRS can be used as a standard method for the analysis of forages. The method has been adopted official first action.

Moisture Analysis of Forage by Near Infrared Reflectance Spectroscopy: Preliminary Collaborative Study and Comparison Between Karl Fischer and Oven Drying Reference Methods

Abstract A collaborative study of moisture analysis by neai infrared reflectance spectroscopy (NIRS) has been completed involving 5 laboratories and 20 forage samples. Near infrared reflectance spectroscopy calibrations for moisture were developed in the Associate Referee's laboratory from Karl Fischer (KF) and AOAC air oven (AO) (135°C for 2 h) moisture methods, respectively, and transferred to each collaborating laboratory's NIRS instrument. NIRS moisture data were validated with KF data from the Associate Referee's laboratory and AO data from each collaborating laboratory. The standard error of analysis of KF data by NIRS KF determination and AO data by NIRS AO determination ranged from 0.25 to 0.48% and from 0.74 to 1.88%, respectively. The standard errors between laboratories for NIRS KF and NIRS AO determinations were 0.2" and 0.39%, respectively. The standard error between moisture analyses by NIRS KF and NIRS AO calibrations, averaged across laboratories, was 0.42%. In addition, the standard error between laboratories for the AOAC AO method was 0.63%. The increase in standard error for the AOAC AO method was due to the random and systematic errors associated with the gravimetric techniques. The results indicate that NIRS analysis can accurately and precisely deterrr ine the moisture content of forages and forage crops because of th« very strong absorbance of water in the near infrared region.

Electron Capture Gas-Liquid Chromatographic Determination of Methyl Mercury in Fish and Shellfish: Collaborative Study

A method for determining methyl mercury in fish and shellfish was collaboratively studied in 8 laboratories. Methyl mercury is isolated from acetone-washed, homogenized tissue by adding hydrochloric acid and extracting into benzene the methyl mercuric chloride that is formed. The benzene extract is concentrated and analyzed for methyl mercuric chloride by electron capture gas-liquid chromatography on 5% DEGS-PS treated with inorganic mercuric chloride solution. The quantitation limit for the method is 0.05 micrograms Hg/g. Each collaborator determined methyl mercury at 2 levels in blind duplicate samples of swordfish, tuna, oyster, and shrimp tissues. Both fortified and unfortified samples were analyzed. Methyl-bound mercury in the samples ranged from 0.15 to 2.48 micrograms Hg/g. The reproducibility coefficients of variation for the 8 samples ranged from 3 to 13%. The accuracy, measured by comparison to reference values, ranged from 99 to 120%. Reference values were determined in the Associate Referee's laboratory by replicate analyses of the fortified and unfortified samples. The method has been adopted official first action.

Interlaboratory comparison of university hospital referee laboratories and community hospital laboratories, using results of the 1968 College of American Pathologists clinical chemistry survey.

Copeland, Bradley E., Skendzel, Laurence P., and Barnett, Roy N.: Interlaboratory comparison of university hospital referee laboratories and community hospital laboratories, using results of the 1968 College of American Pathologists clinical chemistry survey. Am. J. Clin. Pathol. 58: 281–296, 1972. The performances of 58 to 112 university hospital laboratories and 1,300 to 1,700 clinical laboratories participating in the 1968 College of American Pathologists Comprehensive Clinical Chemistry Survey were compared. Each laboratory received eight identical lyophilized samples which were analyzed for eight to 12 chemical constituents. Although the university hospitals performed better, as would be expected, the difference from other laboratories was small. The ± 2 SD “state of the art” criterion used to evaluate performance in national surveys was found to be valid because it provides equally narrow or narrower ranges than those provided by the 99.73% range (3 SD) of university hospitals. Certain systematic differences were observed: these included (1) participant values too high for low sodium levels and too low for high sodium levels; (2) participant values too high for cholesterol and too low for uric acid. The findings indicate a need for particular attention to causes of mferlaboratory variability, which are shown to contribute a significantly greater amount than intralaboratory variability to the total variability of clinical chemical analyses of identical survey samples.

Results from checking of standard sample 1/65 in USSR geochronological laboratories

Pending design of the special reference standard for the potassium-argon method, the 1/65 standard may be used tentatively, under certain provisions, in view of the significant discrepancies in the results obtained by the 26 referee laboratories (table 1) and of the proved need of improving the reliability of determinations of argon, potassium, as well as of the isotopic analysis of argon. – V. P. Sokoloff.

Determination of Starch and Soluble Carbohydrates. II. Collaborative Study of Starch Determination in Cereal Grains and Cereal Products

Abstract The method of Friedemann, Witt, and Neighbors for starch in cereal foods was studied collaboratively on 12 samples by 8 laboratories. Results were compared with those obtained in the Associate Referee's Laboratory and were generally somewhat lower, probably because of inexperience with the method. The method is recommended for adoption as official, first action.

Report on Rotenone

Journal Article Report on Rotenone Get access Romeo Payfer Romeo Payfer Associate Referee Laboratory Unit, Plant Products Division, De partment of Agriculture, Ottawa, Ontario, Canada Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Agricultural Chemists, Volume 41, Issue 3, 1 August 1958, Pages 515–516, https://doi.org/10.1093/jaoac/41.3.515a Published: 07 February 2020

Report on Rotenone

Journal Article Report on Rotenone Get access R Payfer R Payfer Associate Referee Laboratory Services, Plant Products Division, Department of Agriculture, Ottawa, Ontario, Canada Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Agricultural Chemists, Volume 40, Issue 3, 1 August 1957, Page 750, https://doi.org/10.1093/jaoac/40.3.750 Published: 24 January 2020

Report on Riboflavin.

Journal Article Report on Riboflavin. Get access Lawrence Rosner Lawrence Rosner Associate Referee Laboratory of Vitamin Technology, Chicago 19, Ill Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Agricultural Chemists, Volume 37, Issue 3, 1 August 1954, Pages 770–771, https://doi.org/10.1093/jaoac/37.3.770 Published: 23 January 2020