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Analysis of 17 α-hydroxyprogesterone in bloodspots by liquid chromatography tandem mass spectrometry
Simon J Salter1, Paul Cook2, Justin H Davies2
1Royal Free London NHS Foundation Trust, London, UK.
Background:
Monitoring of treatment for patients diagnosed with congenital adrenal hyperplasia (CAH) can be performed by measuring the concentration of 17α-hydroxyprogesterone (17OHP) in bloodspots collected on filter papers. A method is described here for measuring 17OHP by liquid chromatography tandem mass spectrometry (LCMSMS).
Methods:
17OHP was extracted by liquid-liquid extraction and analysed by LCMSMS. The method was validated for sensitivity, specificity, linearity, recovery, ion suppression, precision and bias.
Results:
The standard curve was linear from 0 to 400 nmol/L. Intra-assay %CVs were <10 and inter-assay %CVs were <15 over the range 10-200 nmol/L. Limit of quantitation was 6 nmol/L. No ion suppression was detected. The only interfering compound detected was deoxycorticosterone, an intermediate steroid with the same molecular weight as 17α-hydroxyprogesterone. The method was more accurate and precise than an existing radioimmunoassay. There was poor correlation between the two assays.
Conclusions:
We have developed a sensitive and specific assay suitable for quantitation of 17OHP in bloodspots. This method performs better than radioimmunoassay and allows smaller samples to be used.