Initial Results with a Commercial Luminescence Enhanced Enzyme Immunoassay for the Determination of Carcinoembryonic Antigen (CEA) in Body Fluids
Clinical Chemistry and Laboratory Medicine
A commercially available luminescence enhanced enzyme immunoassay (Amerlite -Amersham International) for carcinoembryonic antigen (CEA) was compared with an established enzyme immunoassay (Monoclonal 1-step Assay -Abbott Laboratories). A reference ränge for healthy blood donors (n = 272) was established for both kits. The blood donors were not separated into smokers and non-smokers, but were excluded from the reference group if they showed abnormal aminotransferase or -glutamyltranspeptidase
... yltranspeptidase serum values. Twenty eight donors were excluded in this way. The test group consisted of 130 known tumour patients, and included pre-and post-operative serum samples. Normal and elevated CEA values were present. All sera were negative for HBsAg, anti-HBsAg and anti-HIV äs determined with commercial enzyme immunoassays used routinely in the blood bank. ** The luminescence enhanced immunoassay gave rise to a reference ränge (95% confidence limits) of less than 3.91 g/l in comparison with the enzyme immunoassay, which had a reference ränge of less than 4.12 g/l. The proportion of elevated values in the tumour patient group was 37/130 for the luminescence enhanced enzyme immunoassay and 28/130 for the enzyme immunoassay. The correlation of values from both methods in the blood donor group was good (r = 0.771, n = 272). The CEA levels found in the tümötir patient group differed significantly when measured in both kits (Wilcoxon matched-pair signed rank test ·-c-alpha = -6.52, p < 0.01, n = 130), the Amersham kit giving the higher results (median values -Abbott 2.35 ^/l, Amersham 2.50 g/l). Although the CEA coticenträtions in the blood donor group were similar for both kits (median values -Abbott 1.12 £ , Amershain 0.92 g/l), the Abbott kit gave significantly higher results statistically (Wilcoxon matched^pair signed rank test -c-alpha = -3.55, p < 0.01, n == 272). From dilution studies, the lower limit öf detection for both assays was set at 0.25 g/l CEA in serum, all values below this being given äs not detectable. As in the case of mäny other kits, the Standards could not be interchanged, although both were calibrated against the international reference prepafation WMO 73/601. The luminescence enhanced enzyme immunoassay can be included in the list of non-isotopic immunoassays for CEA, although, like its competitors, it can only be used in the follow-up of tumour patients, and not äs a screening test.