The development of decision limits for the implementation of the GH-2000 detection methodology using current commercial insulin-like growth factor-I and amino-terminal pro-peptide of type III collagen assays.
BACKGROUND
The GH-2000 project developed a method for detecting GH misuse based on the measurement of insulin-like growth factor-I (IGF-I) and the amino-terminal pro-peptide of type III collagen (P-III-NP). The objective of this study was to develop decision limits for the GH-2000 score to detect GH misuse in elite athletes using two currently available commercial assays for each analyte.


METHODS



METHODS
404 male (mean age 23.9 yrs, range 12-37 yrs) and 94 female elite athletes (mean age 24.5 yrs, range 18-34 yrs) participated. Blood samples were collected according to World Anti-Doping Agency (WADA) guidelines at various sporting events including 238 samples collected as part of the UK Anti-Doping Testing Programme. Laboratory analysis: IGF-I was measured by Siemens Immulite IGF-I assay and Immunotech A15729 IGF-I IRMA. P-III-NP was measured by RIA-gnost P-III-P and the UniQ™ PIIINP RIA.


METHODS
The GH-2000 score decision limits were developed through the analysis of the elite athlete samples.


RESULTS
For males and females separately, the distributions of GH-2000 scores were consistent with Normal distributions. Using a specificity of 99.99% new decision limits were determined which included an allowance for uncertainty associated with calculations based on a finite sample size. One outlier was identified with results incompatible with normal physiology and tested positive with the current isoform GH test.


CONCLUSIONS
We have developed decision limits using currently available commercial assays to measure IGF-I and P-III-NP in elite athletes. This should allow the introduction of a test for GH misuse based on the measurement of these GH sensitive biomarkers.
Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, UK.
Ioulietta
I
Erotokritou-Mulligan
Nishan
N
Guha
Michael
M
Stow
E Eryl
EE
Bassett
Christiaan
C
Bartlett
David A
DA
Cowan
Peter H
PH
Sönksen
Richard I G
RI
Holt
D000293:Adolescent; D000328:Adult; D056352:Athletes; D015415:Biomarkers / Q000378:metabolism; D002648:Child; D003094:Collagen / Q000737:chemistry*; D004300:Doping in Sports / Q000379:methods; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D010446:Peptide Fragments / Q000096:biosynthesis*; D010455:Peptides / Q000737:chemistry; D011347:Procollagen / Q000096:biosynthesis*; D012016:Reference Values; D012680:Sensitivity and Specificity; D012737:Sex Factors; D013177:Sports / Q000502:physiology; D015813:Substance Abuse Detection / Q000379:methods / Q000592:standards*
D015415:Biomarkers; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C041876:procollagen Type III-N-terminal peptide; D007334:Insulin-Like Growth Factor I; D003094:Collagen