Received on July 2, 2008
Accepted on November 13, 2008

Drug Monitoring and Toxicology

High-Sensitivity Chemiluminescence Immunoassays for Detection of Growth Hormone Doping in Sports

¹ Medizinische Klinik–Innenstadt, Ludwig-Maximilians-University, Munich, Germany
² SphingoTec GmbH, Borgsdorf, Germany
³ Division of Clinical Endocrinology, Department of Medicine, Campus Mitte, Charité-Universitätsmedizin, Berlin, Germany
⁴ Hospital for Children and Adolescents, University of Leipzig, Germany

^* To whom correspondence should be addressed. E-mail: martin.bidlingmaier{at}med.uni-muenchen.de.

BACKGROUND: Recombinant human growth hormone (rhGH) is abused in sports, but adequate routine doping tests are lacking. Analysis of serum hGH isoform composition has been shown to be effective in detecting rhGH doping. We developed and validated selective immunoassays for isoform analysis with potential utility for screening and confirmation in doping tests.

METHODS: Monoclonal antibodies with preference for pituitary hGH (phGH) or rhGH were used to establish 2 pairs of sandwich-type chemiluminescence assays with differential recognition of rhGH (recA and recB) and phGH (pitA and pitB). We analyzed specimens from volunteers before and after administration of rhGH and calculated ratios between the respective rec- and pit-assay results.

RESULTS: Functional sensitivities were <0.05 µg/L, with intra- and interassay imprecision 8.4% and 13.7%, respectively. In 2 independent cohorts of healthy subjects, median rec/pit ratios (range) were 0.84 (0.09–1.32)/0.81 (0.27–1.21) (recA/pitA) and 0.68 (0.08–1.20)/0.80 (0.25–1.36) (recB/pitB), with no sex difference. In 20 recreational athletes, ratios (median SD) increased after a single injection of rhGH, reaching 350% (73%) (recA/pitA) and 400% (93%) (recB/pitB) of baseline ratios. At a moderate dose (0.033 mg/kg), mean recA/pitA and recB/pitB ratios remained significantly increased for 18 h (men) and 26 h (women). After high-dose rhGH (0.083 mg/kg), mean rec/pit ratios remained increased for 32 h (recA/pitA) and 34 h (recB/pitB) in men and were still increased after 36 h in women.

CONCLUSIONS: Using sensitive chemiluminescence assays with preferential recognition of phGH or rhGH, detection of a single injection of rhGH was possible for up to 36 h.