Accuracy assessment of the immunochromatographic method (rapid test) for the qualitative determination of prostate-specific antigen (PSA) in patients from the “Novembro Azul” campaign

Abstract:

Prostate cancer is the most common non- -cutaneous tumor and the second cause of death due to tumor among men. The high incidence of clinically diagnosed prostate cancer in the last twenty years reflects the result of an effective screening using prostate-specific antigen (PSA) tests. Electrochemiluminescence (ECLIA) still remains the gold standard method for determining serum PSA. However, faster and more straightforward methods are available on the market, which are usually based on the qualitative immunochromatographic method that informs whether serum PSA levels are above 4 ng / mL, whose concentrations are present in 70 to 80% of the patients with malignant prostate tumors. The aim of this work is to demonstrate the accuracy of the qualitative immunochromatographic method in comparison with the results from the quantitative ELISA tests. 212 men aged between 39 and 101 were used in this study, where three blood aliquots were withdrawn, one for the ECLIA test and the other two for the immunochromatographic tests with kits from two different manufacturers. 3.3% of the individuals had PSA content within the range of 4 to 7 ng / mL (values with prediction of malignancy of 30%). In this range, 42.9% of the immunochromatographic tests of brand A and 71.4% of brand B showed positive results. In the range above 7 ng / mL (2.8% of the samples), 100% of both tests were positive. Immunochromatographic tests had an average sensitivity of 77.5% at those PSA contents near their detection limits and 100% in samples with PSA contents at an upper range, where 95% of prostate tumors can be detected in association with other tests. Therefore, the immunochromatographic tests seem to be satisfactory when used in screening patients with prostatic neoplasia, especially if we take into account the simplicity and the low cost of this method.


Keywords: PSA. ECLIA. Prostatic neoplasia. Accuracy. Immunochromatography

Authors:
Naiche Abdon Miranda;
Jonathan Jenzer;
Irami de Araújo-Filho;
Fausto Pierdoná Guzen;
Eduardo Pereira de Azevedo

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