posted on 2024-01-26, 18:03authored byMathias
Flensted Poulsen, Martin Overgaard, Christian Brix Folsted Andersen, Andreas Lodberg
Measurement of total
cortisol levels in serum samples is currently
based on immunoassays or liquid chromatography–mass spectrometry
(LC–MS/MS). However, measurement of bioavailable cortisol is
laborious, unreliable, and inconvenient for the patient. Therefore,
a new versatile assay with the ability to measure both total and bioavailable
cortisol from serum represents an important supplement to the current
methods. We have generated a cell-based glucocorticoid reporter assay
(HEK293F-GRE). The assay was validated for cell line stability, accuracy
by dilution, precision, repeatability, reproducibility, and specificity.
Additionally, the assay was tested for measuring both total and bioavailable
cortisol in serum. The assay showed linearity at five dilution levels
with R2 = 0.98 and an accuracy between
0.8 and 1.2. Precision (CV < 20%) was validated down to 3–6
nM dexamethasone, and estimation of the total cortisol concentration
was comparable to cortisol immunoassay and LC–MS/MS in most
serum samples. Moreover, the assay estimated the bioavailable cortisol
fraction in serum samples to a level that agreed with the literature.
The HEK293F-GRE assay holds the potential to be a complementary method
for estimating cortisol in clinical practice. The ability to quantify
bioavailable cortisol directly from serum samples is alluring and
provides an opportunity for monitored and personal dose regimens of
exogenous glucocorticoids.