The effects of a freeze-thaw cycle and pre-analytical storage temperature on the stability of insulin-like growth factor-I and pro-collagen type III N-terminal propeptide concentrations: Implications for the detection of growth hormone misuse in athletes.
Author(s): Guha N, Erotokritou-Mulligan I, Bartlett C, Cowan DA, Bassett EE, Stow M, Sönksen PH, Holt RI
Publication: Drug Test Anal, 2012, Vol. 4, Page 455-9
PubMed ID: 22511534 PubMed Review Paper? No
Purpose of Paper
Conclusion of Paper
Studies
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Study Purpose
The purpose of this study was to determine the effects of storage, a single freeze-thaw cycle, and immunoassay type on measurement of IGF-I and P-III-NP in serum. Specimens were either analyzed immediately, transferred to 4 degrees C for 24 h, analyzed again and then transferred to -20 degrees C for the remainder of the storage.
Summary of Findings:
IGF-I and P-III-NP levels were unaffected by storage of serum for 24 h at 4 degrees C followed by freezing and storage at -20 degrees C for up to 87 days. Further, the GH-2000 score calculated from the IGF-I and P-III-NP levels showed low variability, and the authors state the false-positive rate for performance enhancing drug abuse would be 1:10,000 for the time-points investigated. The intra-specimen and inter-assay CVs in IGF-I measurements were lower using the IRMA than then ELISA. The P-III-NP intra-specimen CV was higher, but the inter-assay CV was lower using the Orion RIA than the Cisbio RIA.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Protein ELISA Protein Immunoradiometric assay Peptide Radioimmunoassay Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Freeze/thaw cycling 0 cycles
1 cycle
Storage Storage duration 0 days
1 day
2 days
8 days
36 days
87 days
ELISA Specific Technology platform IRMA
Radioimmunoassay Specific Technology platform Orion RIA
Cisbio RIA