PMID- 18567697
OWN - NLM
STAT- MEDLINE
DCOM- 20080814
LR  - 20190722
IS  - 1530-8561 (Electronic)
IS  - 0009-9147 (Linking)
VI  - 54
IP  - 8
DP  - 2008 Aug
TI  - Within-subject variability and analytic imprecision of insulinlike growth factor 
      axis and collagen markers: implications for clinical diagnosis and doping tests.
PG  - 1268-76
LID - 10.1373/clinchem.2008.105726 [doi]
AB  - BACKGROUND: The utility of insulinlike growth factor (IGF) axis and collagen 
      markers for a growth hormone (GH) doping test in sport depends on their stability 
      and reproducibility. We sought to determine short-term within-subject variability 
      of these markers in a large cohort of healthy individuals. METHODS: We measured 
      IGF-I, IGF binding protein 3 (IGFBP-3), acid labile subunit (ALS), and the 
      collagen markers N-terminal propeptide of type I procollagen (PINP), C-terminal 
      telopeptide of type I collagen (ICTP), and N-terminal propeptide of type III 
      procollagen (PIIINP) in serum samples obtained on multiple occasions (median 3 
      per participant) over a 2- to 3-week period from 1103 elite athletes (699 men, 
      404 women) ages 22.2 (5.2) years [mean (SD)]. We estimated between-subject and 
      within-subject variances by mixed-effects ANOVA. RESULTS: Within-subject variance 
      accounted for 32% to 36% and 4% to 13% of the total variance in IGF markers and 
      collagen markers, respectively. The within-subject CV ranged from 11% to 21% for 
      the IGF axis markers and from 13% to 15% for the collagen markers. The index of 
      individuality for the IGF axis markers was 0.66-0.76, and for the collagen 
      markers, 0.26-0.45. For each marker, individuals with initial extreme measured 
      values tended to regress toward the population mean in subsequent repeated 
      measurements. We developed a Bayesian model to estimate the long-term probable 
      value for each marker. CONCLUSIONS: These results indicate that in healthy 
      individuals the within-subject variability was greater for IGF-I than for the 
      collagen markers, and that where a single measurement is available, it is 
      possible to estimate the long-term probable value of each of the markers by 
      applying the Bayesian approach. Such an application can increase the reliability 
      and decrease the cost of detecting GH doping.
FAU - Nguyen, Tuan V
AU  - Nguyen TV
AD  - Garvan Institute of Medical Research and Department of Endocrinology, Sydney, 
      Australia.
FAU - Nelson, Anne E
AU  - Nelson AE
FAU - Howe, Christopher J
AU  - Howe CJ
FAU - Seibel, Markus J
AU  - Seibel MJ
FAU - Baxter, Robert C
AU  - Baxter RC
FAU - Handelsman, David J
AU  - Handelsman DJ
FAU - Kazlauskas, Ray
AU  - Kazlauskas R
FAU - Ho, Ken K
AU  - Ho KK
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080620
PL  - England
TA  - Clin Chem
JT  - Clinical chemistry
JID - 9421549
RN  - 0 (Biomarkers)
RN  - 0 (Insulin-Like Growth Factor Binding Protein 3)
RN  - 67763-96-6 (Insulin-Like Growth Factor I)
RN  - 9002-72-6 (Growth Hormone)
RN  - 9007-34-5 (Collagen)
SB  - IM
CIN - Clin Chem. 2008 Aug;54(8):1265-7. PMID: 18664441
MH  - Adult
MH  - Analysis of Variance
MH  - Biomarkers/blood
MH  - *Clinical Laboratory Techniques/methods/standards
MH  - Cohort Studies
MH  - Collagen/*analysis/blood
MH  - Doping in Sports/*prevention & control
MH  - Female
MH  - Growth Hormone/*blood
MH  - Humans
MH  - Insulin-Like Growth Factor Binding Protein 3/blood
MH  - Insulin-Like Growth Factor I/*analysis
MH  - Male
MH  - Sensitivity and Specificity
MH  - Sports/*standards
MH  - *Substance Abuse Detection/methods/standards
EDAT- 2008/06/24 09:00
MHDA- 2008/08/15 09:00
CRDT- 2008/06/24 09:00
PHST- 2008/06/24 09:00 [pubmed]
PHST- 2008/08/15 09:00 [medline]
PHST- 2008/06/24 09:00 [entrez]
AID - clinchem.2008.105726 [pii]
AID - 10.1373/clinchem.2008.105726 [doi]
PST - ppublish
SO  - Clin Chem. 2008 Aug;54(8):1268-76. doi: 10.1373/clinchem.2008.105726. Epub 2008 
      Jun 20.