The analytical specificity of human chorionic gonadotropin assays determined using WHO International Reference Reagents

Jo Dell Whittington, Corinne R. Fantz, Ann M. Gronowski, Christopher McCudden, Richard Mullins, Lori Sokoll, Carmen Wiley, Andy Wilson, David G. Grenache

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Background: Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone with considerable molecular heterogeneity. There is uncertainty regarding which hCG variants are detected by different hCG assays. The analytical specificity of 8 hCG assays was investigated. Methods: WHO International Reference Reagents for hCG, nicked hCG (hCGn), beta subunit (hCGβ), nicked beta subunit (hCGβn), and beta core fragment (hCGβcf) were individually added to hCG-free human serum. Specimens were analyzed with 8 commercially available hCG assays. Equimolar detection of hCG variants was defined as a recovery of 90-110%. Results: All assays detected hCG and hCGn with mean recoveries of 98.3 and 94.6%, respectively. Seven assays detected hCGβ (mean recovery 103.8%) but with high variation, and equimolar detection was observed only in four. The mean recovery of hCGβn was 85.5% but was highly variable with only two assays showing equimolar detection. With a mean recovery of 53.4%, two assays detected hCGβcf and both underestimated it considerably. Information provided by the assay manufacturer regarding hCG variant analytical specificity was inadequate or unclear in 75% of the assays. Conclusions: hCG assays vary considerably in their ability to detect different hCG variants. Manufacturers of hCG assays should clearly indicate the hCG variant specificity of their reagent systems.

Original languageEnglish (US)
Pages (from-to)81-85
Number of pages5
JournalClinica Chimica Acta
Issue number1-2
StatePublished - Jan 4 2010


  • Analytical specificity
  • Human chorionic gonadotropin
  • International Reference Reagents

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Biochemistry, medical


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