Vol 86, No 3 (2015)
ARTICLES
Spuriously high androstendione concentrations due to assay interference as a cause of diagnostic conundrum in women with oligomenorrhoea
DOI: 10.17772/gp/2067
Ginekol Pol 2015;86(3).
Abstract
Polycystic ovary syndrome (PCOS) is a diagnosis of exclusion. We present two cases of women with
oligomenorrhoea and high concentration of androstendione, suggestive of possible androgen-secreting tumour,
caused by assay interference. The first patient, investigated for oligomenorrhoea, had no significant hirsutism
or acne. Androstendione concentration was above 10.0 ng/ml (rr: 0.3-3.3 ng/ml). In order to rule out possible
androgen-secreting tumour or hypercortisolaemia we performed 48-hour low dose dexamethasone suppression
test (LDDST). This failed to demonstrate adequate suppression of androstendione (6.05 ng/ml and 9.32 ng/ml
after the first and the second day, respectively). Pelvic ultrasound examination showed polycystic ovaries, while
abdominal CT scan failed to show any ovarian or adrenal lesion. Despite such high androstendione concentrations,
urinary steroid profile (gas chromatography/mass spectrometry method) yielded normal results. Hence a possibility
of androstendione assay interference was raised.
The second patient was also admitted for investigations of oligomenorrhoea. Clinical examination was unremarkable.
There was a high concentration of testosterone 0.78 ng/ml (rr: 0.084-0.481 ng/ml) and androstendione above 10.0
ng/ml (rr: 0.3-3.3 ng/ml). LDDST failed to demonstrate any suppression of androstendione, while recalculated
concentrations of androstendione after serial dilutions were markedly lower in comparison to initial values. Therefore,
such high androstendione concentrations (i.e. above the upper limit of the assay) must have resulted from assay
interference. In both cases a final diagnosis of PCOS was established.
Conclusions: In the absence of clinical features, contrasting with unusually high androgen levels, a possibility of
androgen assay interference should be considered in differential diagnosis of hyperandrogenism or PCOS.
Keywords: hyperandrogenism / androgens / androstendione / assay interference
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