Poster Presentation ESA-SRB-APEG-NZSE 2022

Investigating serum 21-deoxycortisol for therapeutic monitoring of classic congenital adrenal hyperplasia (#306)

Lauren Tyack 1 2 , Jennifer Ng 3 4 5 , Ee Mun Lim 1 6 , Rui Zhang 6 , Suzanne Brown 1 , Bronwyn Stuckey 1 3 7
  1. Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital , Nedlands, WA, Australia
  2. Department of Endocrinology and Diabetes, Fiona Stanley Hopsital , Murdoch, WA, Australia
  3. Keogh Institute for Medical Research , Nedlands, WA, Australia
  4. Hollywood Consulting Centre, Nedlands, WA, Australia
  5. King Edward Memorial Hospital, Subiaco, WA, Australia
  6. Biochemistry , PathWest QEII, Nedlands, WA, Australia
  7. Medical School , University of Western Australia, Nedlands, WA, Australia

 

Biochemical monitoring of classical 21-hydroxylase-deficient congenital adrenal hyperplasia (CAH) mostly relies on measurement of serum 17-hydroxyprogesterone (17OHP) and androstenedione (A4) concentrations. However, high biological variability, particularly of 17OHP, limits interpretation of results and makes therapeutic adjustments based on single measurements challenging. Recently, 21-deoxycortisol (21DF), has been proposed as a more reliable marker of disease control owing to its adrenal-specific origin and lower biological variability.

Our objective was to compare the intra-individual variability of serum 17OHP, A4 and 21DF, all quantified by liquid chromatography and tandem mass spectrometry (LC-MS/MS) in a cohort of patients with classical salt-wasting CAH. 

32 adults (9 males and 23 females) with salt wasting CAH were identified from a single institution. All LC-MS/MS quantified 17OHP, A4 and 21DF measurements performed at PathWest QEII Laboratory between 01/01/2018 and 04/05/2022 were collated for each patient. 20 patients had 2 or more 21DF measurements. Of these, 40 % had 5 or more measurements. The biological component of each patient’s intra-individual coefficient of variation (CVI) was calculated for each analyte. The intra-individual variability was compared between the analytes.

There was strong statistical evidence of lower biological variability (CVI) for A4 than 17OHP (mean difference = -24.1, p=0.003). Other pairwise differences were not significant (A4 versus 21DF p=0.156; 21DF versus 17OHP p=0.104).

The intra-individual variability of LC-MS/MS-quantified 21DF was similar to A4 in adult patients with salt-wasting CAH. Larger prospective studies are required to determine the clinical utility of 21DF measurement for therapeutic monitoring of CAH.

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