Endocrine Abstracts

There has been controversy over the diagnostic utility of the LH/FSH ratio in polycystic ovarian syndrome, with more recent guidelines excluding it as a diagnostic test. However, LH/FSH is still often requested for that purpose and in our institution, 20% of the 12,000 annual requests for LH/FSH tests requested in a one year period had PCOS detailed on the card, at a cost of over £37,000.

Objective: The aim of this study was to ascertain the biological variability of the LH/FSH ratio in women with PCOS in comparison to those with normal menstruation over a full cycle, in order to determine whether the ratio had diagnostic utility when assessed in this manner.

Method: Blood samples were collected at 4 day intervals on 10 consecutive occasions from 12 PCOS patients and 11 age- and weight-matched controls. All subjects gave their informed written consent before entering the study, which was approved by the Hull and East Riding local research ethics committee. Duplicate samples were analysed for LH and FSH in a single batch.

Results: The inter and intra-individual variances were found to be high and similar between PCOS (16% and 83%, respectively) and the control group (23% and 76%, respectively) as well as in anovulatory PCOS subgroup (33% and 66%, respectively). Only 7.6% of samples from PCOS patients and 15.6% of those from normal subjects had a LH/FSH ratio above 3, the recommended cut off value.

Conclusion: These data showed that the biological variation of the LH/FSH ratio is at least as wide for normal women as it is for those with PCOS indicating why the ratio has little diagnostic utility for PCOS, in support of the Rotterdam polycystic ovary syndrome consensus.