Background: It remains unclear whether specimen repeated freeze-thaw cycles can influence urinary lutenising hormone (LH) and follicular stimulating hormone (FSH) assayed by immunochemiluminometric assays (ICMA).
Objective and hypotheses: To investigate the effect of specimen repeated freeze-thaw cycles on urinary LH and FSH determined by ICMA.
Method: The first morning-voided urine was collected and divided two parts. One part was stored at −20°C (Frozen Sample), and the other was stored at 4°C. Urinary LH and FSH were assayed by ICMA between 0 and 13 freeze-thaw cycles (between 0 and 14 days).
Results: Compared with the original specimen, urinary LH for all specimen were unaffected from the first to the second days, and urinary FSH within 14 days for all specimen, too. The correlation between urinary LH in Frozen Sample as a percentage of original LH and freeze-thaw cycles was −0.879, for urinary FSH as a percentage of original FSH was 0.102.
Conclusion: When urinary specimen are stored at −20°C, ICMA can measure urinary LH within two freeze-thaw cycles, and FSH up to 13 freeze-thaw cycles.
Funding: This work was supported by Scientific Research Projects of regular institutions of higher education for postgraduates in Jiangsu province (grant numbers:CXLX13_828), and Scientific Research Projects of Wuxi city in Jiangsu province (grant numbers:Q201204).
01 - 03 Oct 2015
European Society for Paediatric Endocrinology