Technical performance and diagnostic utility of the new Elecsys (R) neuron-specific enolase enzyme immunoassay

This international multicenter study was designed to evaluate the
technical performance of the new double-monoclonal, single-step
Elecsys neuron-specific enolase (NSE) enzyme immunoassay (EIA) and
to assess its utility as a sensitive and specific test for the
diagnosis of small-cell lung cancer (SCLC). Intra and interassay
coefficients of variation, determined in five control or serum
specimens in six laboratories, ranged from 0.7 to 5.3
(interlaboratory median: 1.3%) and from 1.3 to 8.5 (interlaboratory
median: 3.4%), respectively. Laboratory-to-laboratory comparability
was excellent with respect to recovery and interassay coefficients
of variation. The test was linear between 0.0 and 320 ng/ml
(highest measured concentration). There was a significant
correlation between NSE concentrations measured using the Elecsys
NSE and the established Cobas Core NSE EIA II in all subjects
(n=723) and in patients with lung cancer (n=333). However, NSE
concentrations were systematically lower (approximately 9%) with
the Elecsys NSE than with the comparison test. Based on a
specificity of 95% in comparison with the group suffering from
benign lung diseases (n=183), the cutoff value for the
discrimination between malignant and benign conditions was set at
21.6 ng/ml. NSE was raised in 73.4% of SCLC patients (n=188) and
was significantly higher (p