Inter-laboratory validation of the measurement of follicle stimulating hormone (FSH) after various lengths of frozen storage

Abstract

BackgroundSerum follicle stimulating hormone (FSH) levels are used clinically to evaluate infertility, pituitary and gonadal disorders. With increased frequency of research collaborations across institutions, it is essential that inter-laboratory validation is addressed.MethodsAn inter-laboratory validation of three commercial FSH immunoassays was performed with human serum samples of varying frozen storage length (2 batches of 15 samples each) at -25 degree C. Percentage differences and Bland-Altman limits of agreement were calculated.ResultsThe inter- and intra-laboratory consistency of FSH values with the same assay manufacturer was much higher after shorter-term storage (frozen for less than 11 months, mean percentage degradation less than 4%) than after long-term storage (2-3 years, mean percentage degradation = 23%). Comparing assay results from different manufacturers, there was similar overall long term degradation as seen with the same manufacturer (-25%), however the degradation was greater when the original FSH was greater than 20 mIU/mL relative to less than 10 mIU/mL (p < 0.001 trend test).ConclusionThe findings suggest that degradation of serum samples stored between 11 months and 2-3 years at -25 degrees C can lead to unstable FSH measurements. Inter-laboratory variability due to frozen storage time and manufacturer differences in assay results should be accounted for when designing and implementing research or clinical quality control activities involving serum FSH at multiple study sites.

Stability of selected serum hormones and lipids after long-term storage in the Janus Serum Bank

“…We found FSH particular stable in contrast to Scriver et al [41] who reported 23% mean percentage degradation of FSH in serum stored at −20°C for 2−3 years.…”

Effect of cold stress on physicochemical characteristics and biological activity of equine chorionic gonadotropin

“…Probably, the deleterious effect of storage time on eCG follows the pattern of the gonadotropin FSH, which shows a slight decrease (2.8%) in immunoreactivity after a week of storage at 4 or -20°C and about a 40% decrease after 64 weeks (Scriver et al, 2010). One weakness of our study is that we did not compare the results with a reference standard curve of dose-response in each assay; thus, we cannot quantify the eventual loss of biological potency.…”

Attitudes Towards Potentially Carrying the FMR1 Premutation: Before vs After Testing of Non‐Carrier Females with Diminished Ovarian Reserve

“…Knowing that FSH values can vary by assay (Scriver, Baker, Young, Behr, & Pastore, 2010; Taieb et al, 2002), de-identified samples were run at each satellite site and the primary site (University of Virginia), and adjusted accordingly to ensure consistency in the enrollment criteria across sites as described previously (Pastore et al, 2012; Scriver et al, 2010). …”

“…The criteria for exclusion were: known cause of elevated FSH for one's age unrelated to fragile X (e.g., surgical removal of either one or both ovaries, chemotherapy or radiation therapy, Turners Syndrome, autoimmune disease), or a family history of FXS or premutation. Knowing that FSH values can vary by assay (Scriver et al 2010;Taieb et al 2002), deidentified samples were run at each satellite site and the primary site (University of Virginia), and adjusted accordingly to ensure consistency in the enrollment criteria across sites as described previously (Pastore et al 2012;Scriver et al 2010).…”