A determination of the pre-analytical storage conditions for insulin like growth factor-I and type III procollagen peptide.
OBJECTIVE
IGF-I and type III procollagen (P-III-P) have been proposed as markers to detect GH abuse. This study aims to determine whether the pre-analytical storage temperature or delayed centrifugation affect the measured IGF-I and P-III-P concentrations.


METHODS
Observational study.


METHODS
Wellcome Trust Clinical Research Facility, Southampton.


METHODS
Nineteen healthy volunteers.


METHODS
Blood was collected into bottles containing a clotting agent, lithium heparin or EDTA. One sample from each group was centrifuged and stored at -80 degrees C (control sample). The remaining samples from each group were stored as either serum or whole blood at 4 degrees C or room temperature for up to five days prior to storage at -80 degrees C.


METHODS
IGF-I and P-III-P.


RESULTS
The storage temperature or timing of centrifugation did not appear to affect IGF-I concentration. In contrast, the measured P-III-P concentration rose by 6.5-7% per day in clotted and lithium heparin samples when stored as whole blood (p<0.006) or serum (6.2-6.5% per day) at room temperature (p<0.001). P-III-P did not change when the samples were stored at 4 degrees C. Although collection into EDTA inhibited the rise in P-III-P, the baseline measured values were significantly higher than in other media and spiking experiments demonstrated that EDTA exerted a significant matrix effect on the assay.


CONCLUSIONS
While the optimum collection method is immediate centrifugation and storage at -80 degrees C, it would seem acceptable to store serum or clotted blood samples at 4 degrees C, but not ambient temperature, for up to five days. It is incumbent on the anti-doping authorities to provide facilities to allow this.
Holt
Richard I G
RI
Endocrinology and Metabolism Sub-Division, Developmental Origins of Adult Health and Disease Division, School of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom. R.I.G.Holt@soton.ac.uk
Erotokritou-Mulligan
Ioulietta
I
Ridley
Sean A
SA
McHugh
Cathy M
CM
Bassett
E Eryl
EE
Cowan
David A
DA
Bartlett
Christiaan
C
Sönksen
Peter H
PH
D001793:Blood Preservation / Q000379:methods*; D001800:Blood Specimen Collection / Q000379:methods*; D024061:Collagen Type III / Q000097:blood / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D006493:Heparin / Q000737:chemistry; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000737:chemistry*; D013696:Temperature
D024061:Collagen Type III; D007334:Insulin-Like Growth Factor I; D006493:Heparin; D004492:Edetic Acid