High-Dose Hook Effect in 17-Hydroxyprogesterone Assay in a Patient with 21-Hydroxylase Deficiency

Abstract

Congenital adrenal hyperplasia (CAH) describes a group of disorders characterized by enzyme defects in adrenal steroidogenesis. 21-hydroxylase deficiency (21-OHD) is the most commonly encountered form. The analysis of steroids in pediatric cases requires high-sensitivity assays. A 14-year-old Syrian girl was referred for evaluation of short stature, amenorrhea, and hirsutism. On physical examination, breast development was Tanner stage 1. She had a phallic clitoris with a single urogenital orifice. Laboratory findings revealed primary adrenal deficiency with high androgen levels and low levels of 17-hydroxyprogesterone (17-OHP), (<0.05 ng/mL) and estrogen. This unexpected result led to suspicion of a high-dose hook effect. The measurement was repeated after 1/10 dilution of serum, and a high level of 17-OHP (115.4 ng/mL) was detected with the same test-enzyme-linked immunosorbent assay (ELISA). Simple virilizing form of CAH (21-OHD) was suspected and confirmed with genetic analysis. After initiation of glucocorticoid therapy, breast development was noted along with a decrease in testosterone level and an increase in estrogen level. To our knowledge, this is the first case report of hook effect for 17-OHP immunoassay in a patient with 21-OHD. High-dose hook effect should be suspected in patients with CAH when the test results are incompatible with one another. Additionally, this case demonstrates that a high testosterone level can block aromatase activity and consequently also estrogen production and breast development.

Quantification of pharmacokinetic profiles of a recombinant canine PD-1 fusion protein by validated sandwich ELISA method

“…In addition, the accuracy and precision were validated by more different concentrations, replicates, and batches than the validation of the UPLC-MS/MS method ( 25 , 26 ), and both the precision and accuracy conform to the requirements. The hook effect will cause false-negative at high drug concentrations ( 30 , 31 ), which was detected by adding the recombinant protein concentration over ULOQ. The absorbance values of hook effect samples are higher than that of ULOQ, which means that no hook effect was detected in the established ELISA method.…”

Analytical Methods for the Determination of Neuroactive Steroids

“…Another problem associated with IA may be the so-called high-dose hook effect, which leads to a false undervaluation of the analysis results [ 58 , 59 , 60 , 61 ]. This effect has been observed in the “sandwich” IAs.…”