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Updated: Jul 2, 2026
A Semi-High-Throughput Adaptation of the NADH-Coupled ATPase Assay for Screening Small Molecule Inhibitors
Published on: August 17, 2019
Performance characteristics of the Access Inhibin A assay
Mindy L Rawlins1, Sonia L La'ulu, J Alan Erickson
1ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT 84108, USA.
Background:
Second trimester maternal screening using AFP, uE3, hCG, and inhibin A has shown a detection rate for Down's syndrome of 81% with a 5% false positive rate. Inhibin A may also have utility as a serum tumor marker in postmenopausal women with ovarian cancer and men with testicular stromal tumors.
Methods:
The Beckman Coulter Access Inhibin A assay was evaluated for limit of blank, dilution linearity, imprecision, interferences, reference intervals, and comparison to an inhibin A ELISA.
Results:
The limit of blank was 0.1 ng/l. The assay was linear from 0.2 to 1347 ng/l. Total inter-assay CVs were <5% for control levels ranging from 24.6 ng/l to 811 ng/l. Interference studies showed recoveries of inhibin A within 10% of expected values at interferent concentrations of 10 g/l hemoglobin and 22 g/l triglycerides. No significant interference was observed at a bilirubin concentration of 400 mg/l. The 97.5th percentile upper reference limits were 6.8 ng/l for postmenopausal women and 3.0 ng/l for men. The Access assay compared to an ACTIVE ELISA showed a slope of 0.88, an intercept of -3.7 ng/l, S(y/x)=40 ng/l, and r=0.98.
Conclusions:
The analytical performance of the Access inhibin A assay is acceptable for routine laboratory testing.
