+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

A comparison of human chorionic gonadotropin- related components in fresh frozen serum with the proficiency testing material used by the College of American Pathologists



A comparison of human chorionic gonadotropin- related components in fresh frozen serum with the proficiency testing material used by the College of American Pathologists



Archives of Pathology & Laboratory Medicine 129(3): 328-330



As part of a College of American Pathologists (CAP) proficiency testing survey, a comparison is made between human chorionic gonadotropin (hCG) results from an actual patient pool and a similarly targeted artificial sample. The goal is to gain insight into the possible source(s) of bias attributable to the proficiency testing material (PTM) with a view toward creating more appropriate survey materials. To compare hCG and related variants in a pool of fresh frozen sera (FFS) with that found in PTM. The 2003 CAP K/KN-A Survey included a FFS specimen along with admixtures of PTM. The FFS (K-02) and 1 PTM admixture (K-01) had similar mean hCG values. Five hCG-related analytes were measured on these 2 samples by a reference laboratory. Approximately 1800 clinical laboratories and diagnostic test kit manufacturers participated in the K/ KN-A Survey. Method imprecision (coefficient of variation) and method bias (relative difference between peer group mean and all-method median) were computed for the 2 samples. Differences were evaluated with respect to hCG-related analytes levels. All-method hCG results were 12.9 mIU/mL (12.9 IU/L) for the PTM material and 21.6 mIU/mL (21.6 IU/L) for the FFS material. Method biases for 14 manufacturers were greater for PTM than for FFS (-40% to +35% and -16% to +23%). Twelve of 14 methods had higher coefficients of variation on PTM. Total hCG and free beta hCG measurements by the reference laboratory were 14.1 mIU/ mL (14.1 IU/L) for the PTM material and 18.5 mIU/mL (18.5 U/L) for the FFS material (FFS), and 2.4 (PTM) and 0.7 (FFS) mIU/mL (2.4 and 0.7 IU/L), respectively. On a molar basis, free beta represented 17% and 4% of the total hCG, respectively. Levels of hyperglycosylated hCG, nicked hCG, and beta core fragment were not measurable in either sample. It is unlikely that the hCG added to the PTM is the source of the increased bias and variability. The main difference is a 3-fold increase in free beta found in the PTM, but methods previously found to strongly react with free beta were not systematically elevated. The biases between manufacturers found for the FFS specimen are likely attributable to calibration differences.

Please choose payment method:






(PDF emailed within 1 workday: $29.90)

Accession: 048057802

Download citation: RISBibTeXText

PMID: 15737026


Related references

Performance of fresh frozen serum as a proficiency testing material for human chorionic gonadotropin Results of a College of American Pathologists survey. Clinical Chemistry 50(6, Suppl S, Part 2): A93, 2004

Comparison of fresh frozen serum to proficiency testing material in College of American Pathologists surveys: alpha-fetoprotein, carcinoembryonic antigen, human chorionic gonadotropin, and prostate-specific antigen. Archives of Pathology & Laboratory Medicine 129(3): 331-337, 2005

Comparison of pooled fresh frozen serum to proficiency testing material in College of American Pathologists surveys: cortisol and immunoglobulin E. Archives of Pathology & Laboratory Medicine 129(3): 305-309, 2005

Comparison of fresh frozen serum to traditional proficiency testing material in a College of American Pathologists survey for ferritin, folate, and vitamin B12. Archives of Pathology & Laboratory Medicine 129(3): 323-327, 2005

College of American Pathologists 2003 fresh frozen serum proficiency testing studies. Archives of Pathology & Laboratory Medicine 129(3): 292-293, 2005

Bilirubin proficiency testing using specimens containing unconjugated bilirubin and human serum: results of a College of American Pathologists study. Archives of Pathology & Laboratory Medicine 128(11): 1219-1223, 2004

Automatic Failure in Gynecologic Cytology Proficiency Testing: Results From the College of American Pathologists Proficiency Testing Program. Yearbook of Pathology and Laboratory Medicine 2011: 194-195, 2011

Automatic failure in gynecologic cytology proficiency testing. Results from the College of American Pathologists proficiency testing program. Archives of Pathology & Laboratory Medicine 133(11): 1757-1760, 2009

Performance of herpes simplex challenges in proficiency testing: observations from the College of American Pathologists proficiency testing program. Archives of Pathology & Laboratory Medicine 133(9): 1379-1382, 2009

Performance of Candida--fungal-induced atypia and proficiency testing: observations from the College of American Pathologists proficiency testing program. Archives of Pathology & Laboratory Medicine 133(8): 1272-1275, 2009

Human immunodeficiency virus type 1 proficiency testing. The American Association of Blood Banks/College of American Pathologists Program. Archives of Pathology & Laboratory Medicine 114(3): 268-271, 1990

Performance of reference measurement procedures for the College of American Pathologists fresh frozen serum project. Clinical Chemistry 50(6, Suppl S, Part 2): A107, 2004

College of American Pathologists/American College of Medical Genetics proficiency testing for constitutional cytogenomic microarray analysis. Genetics in Medicine 13(9): 765-769, 2012

Multilaboratory evaluation of serum analysis for HLA antibody and crossmatch reactivity by lymphocytotoxicity methods: Results of the American Society for Histocompatibility and Immunogenetics/College of American Pathologists proficiency testing surveys during 1993-2000. Archives of Pathology & Laboratory Medicine 127(2): 149-156, 2003

Update on the College of American Pathologists Experience With High-Risk Human Papillomavirus Proficiency Testing for Cytology. Archives of Pathology & Laboratory Medicine 140(12): 1371-1374, 2016