Background: Numerous laboratories in Italy use radioimmunoassay to determine concentrations of sex hormones (FSH, LH, testosterone). A comparison of assay methods is thus an important starting point for the achievement of universally accepted reference values.
Aim: To carry out an external quality assessment for FSH, LH, and testosterone.
Materials and methods: Fifteen aliquots from 5 serum pools were assayed in multiple replicates by 16 Italian laboratories with 5 automated immunoassays (Abbott Architect, DiaSorin Liaison, Perkin-Elmer AutoDelfia, Roche Elecsys, Siemens Immulite 2000), and 1 radioimmunoassay (Adaltis).
Results: The variance was below 12% for FSH, between 11.61% and 14.76% for LH, and between 9.57% and 12.48% for testosterone. Assay precision was good, except for Elecsys at low concentrations of FSH and for Immulite at low concentrations of LH and testosterone. ARCHITECT showed a negative bias for FSH and LH and a positive bias for testosterone; Liaison a positive bias for LH; Elecsys a positive bias for FSH and a negative bias for testosterone; Immulite a positive bias for FSH; AutoDelfia a negative bias for FSH and a positive bias for testosterone. Reference ranges at the low end varied widely, even among laboratories using the same assay.
Conclusions: The analytical performances of widely used immunoassays for FSH, LH, and testosterone show a fair to strong degree of consistency. A careful evaluation of reference ranges by clinical and laboratory experts needs to be carried out, in order to reach a consensus.