Assay reproducibility and within-person variation of Müllerian inhibiting substance

Objectives: To assess reproducibility of a commercial müllerian inhibiting substance (MIS) assay and evaluate within-person variation in serum MIS levels.

Design: Assay reproducibility was evaluated by measuring MIS in multiple serum aliquots from the same blood collection. Within-person variation was assessed by measuring MIS in serum collected twice from the same individuals.

Setting: Cancer Prevention Biomarker and Genotyping Facility, fox Chase Cancer Center, Philadelphia, Pennsylvania.

Patient(s): Assay reproducibility was evaluated using serum from five volunteers with regular menstrual cycles. Within-person variation was evaluated in serum from 20 premenopausal women who donated blood twice at least 1 year apart.

Intervention(s): For both studies, samples were randomly ordered in batches and laboratory personnel were blinded to which aliquots were from the same subject.

Main outcome measure(s): The MIS was measured by ELISA.

Result(s): Within- and between-batch coefficients of variation (CVs) of the assay were 7.9% and 12.3%, respectively. After deleting one subject with extreme values, these CVs decreased to 7.6% and 7.7%, respectively. Within- and between-subject variance in MIS measurements were 2.19 and 0.31, respectively, and the intraclass correlation coefficient was 0.88 (95% confidence interval .77-.98).

Conclusion(s): The MIS serum concentration is relatively stable over 1 year in premenopausal women and can be measured with good reproducibility using a commercial kit.