Baseline Assessment of 25-Hydroxyvitamin D Reference Material and Proficiency Testing/External Quality Assurance Material Commutability: A Vitamin D Standardization Program Study

2017 ◽  
Vol 100 (5) ◽  
pp. 1288-1293 ◽  
Author(s):  
Karen W Phinney ◽  
Christopher T Sempos ◽  
Susan S-C Tai ◽  
Johanna E Camara ◽  
Stephen A Wise ◽  
...  
Keyword(s):  
Vitamin D ◽  
Quality Assurance ◽  
Reference Material ◽  
Quality Assessment ◽  
Human Serum ◽  
Proficiency Testing ◽  
External Quality Assessment ◽  
External Quality ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D

Abstract The Vitamin D Standardization Program (VDSP) coordinated a study in 2012 to assess the commutability of reference materials and proficiency testing/external quality assurance materials for total 25-hydroxyvitamin D [25(OH)D] in human serum, the primary indicator of vitamin D status. A set of 50 single-donor serum samples as well as 17 reference and proficiency testing/external quality assessment materials wereanalyzed by participating laboratories that used either immunoassay or LC-MS methods for total 25(OH)D. The commutability test materials included National Institute of Standards and Technology Standard Reference Material 972a Vitamin D Metabolites in Human Serum as well as materials from the College of AmericanPathologists and the Vitamin D External Quality Assessment Scheme. Study protocols and data analysis procedures were in accordance with Clinical and Laboratory Standards Institute guidelines. The majority of the test materials were found to be commutable with the methods used in this commutability study. These results provide guidance for laboratories needing tochoose appropriate reference materials and select proficiency or external quality assessment programs and will serve as a foundation for additional VDSP studies.

Establishing an Accuracy Basis for the Vitamin D External Quality Assessment Scheme (DEQAS)

2017 ◽  
Vol 100 (5) ◽  
pp. 1277-1287 ◽  
Author(s):  
Carolyn Q Burdette ◽  
Johanna E Camara ◽  
Federica Nalin ◽  
Jeanita Pritchett ◽  
Lane C Sander ◽  
...  
Keyword(s):  
Vitamin D ◽  
Quality Assessment ◽  
External Quality Assessment ◽  
Measurement Procedure ◽  
Binding Assays ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
Hydroxyvitamin D ◽  
Target Values ◽  
High Concentrations

Abstract Until recently, the Vitamin D External Quality Assessment Scheme (DEQAS) assessed the performance of various assays for the determination of serum total 25-hydroxyvitamin D [25(OH)D] by using a consensus mean based on the all-laboratory trimmed mean (ALTM) of the approximately 1000 participants' results. Since October 2012, the National Institute of Standardsand Technology (NIST), as part of the Vitamin D Standardization Program, has participated in DEQAS by analyzing the quarterly serum sample sets using an isotope dilution LC-tandem MS (ID LC-MS/MS) reference measurement procedure to assign an accuracy-based target value for serum total 25(OH)D. NIST has analyzed90 DEQAS samples (18 exercises × 5 samples/exercise) to assign target values. The NIST-assigned values are compared with the ALTM and the biases assessed for various assays used by the participants, e.g., LC-MS/MS, HPLC, and several ligand-binding assays. The NIST-value assignment process and the resultsof the analyses of the 90 DEQAS samples are summarized. The absolute mean bias between the NIST-assignedvalues and the ALTM was 5.6%, with 10% of the samples having biases >10%. Benefits of the accuracy-based target values are presented, including for sample sets with high concentrations of 25(OH)D2 and 3-epi-25(OH)D3.

External quality assessment: best practice

2014 ◽  
Vol 67 (8) ◽  
pp. 651-655 ◽  
Author(s):  
David James ◽  
Darren Ames ◽  
Berenice Lopez ◽  
Rachel Still ◽  
Wiliam Simpson ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Quality Assessment ◽  
Proficiency Testing ◽  
Best Practice ◽  
Clinical Laboratory ◽  
External Quality Assessment ◽  
External Quality ◽  
Accredited Laboratories ◽  
Eqa Schemes

There is a requirement for accredited laboratories to participate in external quality assessment (EQA) schemes, but there is wide variation in understanding as to what is required by the laboratories and scheme providers in fulfilling this. This is not helped by a diversity of language used in connection with EQA; Proficiency testing (PT), EQA schemes, and EQA programmes, each of which have different meanings and offerings in the context of improving laboratory quality.We examine these differences, and identify what factors are important in supporting quality within a clinical laboratory and what should influence the choice of EQA programme. Equally as important is how EQA samples are handled within the laboratory, and how the information provided by the EQA programme is used.EQA programmes are a key element of a laboratory's quality assurance framework, but laboratories should have an understanding of what their EQA programmes are capable of demonstrating, how they should be used within the laboratory, and how they support quality. EQA providers should be clear as to what type of programme they provide – PT, EQA Scheme or EQA Programme.

Vitamin D supplementation, body weight and human serum 25-hydroxyvitamin D response: a systematic review

2013 ◽  
Vol 53 (2) ◽  
pp. 367-374 ◽  
Author(s):  
Armin Zittermann ◽  
Jana B. Ernst ◽  
Jan F. Gummert ◽  
Jochen Börgermann
Keyword(s):  
Systematic Review ◽  
Vitamin D ◽  
Body Weight ◽  
Human Serum ◽  
Vitamin D Supplementation ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D

Biosafety and quality assurance in the mycology laboratory

2017 ◽  
Author(s):  
Michael D. Palmer ◽  
Shila Seaton
Keyword(s):  
Quality Assurance ◽  
Quality Assessment ◽  
Patient Care ◽  
External Quality Assessment ◽  
Laboratory Setting ◽  
External Quality ◽  
Clinical Mycology ◽  
Optimal Patient Care ◽  
Mycology Laboratory

This chapter examines the roles of biosafety and quality assurance (with emphasis on the importance of external quality assessment) and demonstrates their importance in a clinical mycology laboratory setting. Their practice and combination are required to ensure the provision of precise and accurate analyses in a safety-focused environment to support optimal patient care.

Assessing quality on the Sigma scale from proficiency testing and external quality assessment surveys

2015 ◽  
Vol 53 (10) ◽  
Author(s):  
James O. Westgard ◽  
Sten A. Westgard
Keyword(s):  
Quality Assessment ◽  
Proficiency Testing ◽  
External Quality Assessment ◽  
Objective Assessment ◽  
Analytical Quality ◽  
External Quality ◽  
Proficiency Assessment ◽  
Laboratory Examinations ◽  
Intended Use

AbstractThere is a need to assess the quality being achieved for laboratory examinations that are being utilized to support evidence-based clinical guidelines. Application of Six Sigma concepts and metrics can provide an objective assessment of the current analytical quality of different examination procedures.A “Sigma Proficiency Assessment Chart” can be constructed for data obtained from proficiency testing and external quality assessment surveys to evaluate the observed imprecision and bias of method subgroups and determine quality on the Sigma scale.Data for hemoglobin AAssessment of quality on the Sigma scale provides evidence of the analytical performance that is being achieved relative to requirements for intended use and should be useful for identifying and prioritizing improvements that are needed in the analytical quality of laboratory examinations. In spite of global and national standardization programs, bias is still a critical limitation of current HbA

scholarly journals Proficiency Testing/External Quality Assessment: Current Challenges and Future Directions

2011 ◽  
Vol 57 (12) ◽  
pp. 1670-1680 ◽  
Author(s):  
W Greg Miller ◽  
Graham RD Jones ◽  
Gary L Horowitz ◽  
Cas Weykamp
Keyword(s):  
Quality Assessment ◽  
Proficiency Testing ◽  
External Quality Assessment ◽  
Peer Group ◽  
Measurement Procedure ◽  
Comparison Method ◽  
External Quality ◽  
Group Evaluation ◽  
The Status ◽  
Relationship Of

BACKGROUND Proficiency testing (PT), or external quality assessment (EQA), is intended to verify on a recurring basis that laboratory results conform to expectations for the quality required for patient care. CONTENT Key factors for interpreting PT/EQA results are knowledge of the commutability of the samples used and the process used for target value assignment. A commutable PT/EQA sample demonstrates the same numeric relationship between different measurement procedures as that expected for patients' samples. Noncommutable PT/EQA samples frequently have a matrix-related bias of unknown magnitude that limits interpretation of results. PT/EQA results for commutable samples can be used to assess accuracy against a reference measurement procedure or a designated comparison method. In addition, the agreement of the results between different measurement procedures for commutable samples reflects that which would be seen for patients' samples. PT/EQA results for noncommutable samples must be compared to a peer group mean/median of results from participants who use measurement procedures that are expected to have the same or very similar matrix-related bias. Peer group evaluation is used to asses whether a laboratory is using a measurement procedure in conformance to the manufacturer's specifications and/or in conformance to other laboratories using the same technology. A noncommutable PT/EQA sample does not give meaningful information about the relationship of results for patients' samples between different measurement procedures. SUMMARY PT/EQA provides substantial value to the practice of laboratory medicine by assessing the performance of individual laboratories and, when commutable samples are used, the status of standardization or harmonization among different measurement procedures.

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