Objectives: Over the last years numerous semiquantitative PSA tests have appeared, based on serum or plasma immunochromatography. We present our experience using the SD BIOLINE PSA test, which is performed with plasma or serum for fast qualitative determination of PSA; the cutpoint is 3 ng/ml.
Methods: We analized 54 patients who were admitted in our hospital ward. Two blood samples were obtained from every patient, one for cuantitative PSA determination at the hospital laboratory and the other one for qualitative determination with the SD BIOLINE PSA test, and the results were compared.. Two urologists independently interpreted the test without knowing the PSA values from the lab. To calculate the effect of test reading time, readings were performed at 15, 20 and 25 minutes. Results were classified in a classic contingency table, which enabled us to calculate sensitivity and specificity of the test, as well as positive and negative predictive values.
Results: Mean age was 71. 1 years (range 43-96 yr). From 54 patients in the study 26 (48. 14%) had a PSA > 3 ng/ml (Mean 18.5 ng/ml, range 3.9-66.9 ng/ml) and 28 (51.86%) PSA < 3 ng/ml (mean 0.8 ng/mL, range 0-2.9 ng/mL), in the conventional test. Results for each interval and observer were: 15 min: Observer 1: Sensitivity (S) 76,92%, specificity (E) 100%, positive predictive value (PPV) 100%, negative predictive value (NPV) 82.35%; Observer 2: S 76.92%, E 100%, PPV 100%, NPV 82.35%. 20 minutes: Observer 1: S 100%, E 93.33%, PPV 92.30%, NPV 100%; Observer 2: S 100%, E 93.33%, PPV 92.30%, NPV 100%. 25 minutes: Observer 1: S 100%, E 85.71%, PPV 86.66%, NPV 100%; Observer 2: S 92.30%, E 92.85%, PPV 92.30%, NPV 92.85%.
Conclusions: The SD Bioline PSA test complies with the characteristics required to be used as a test for prostate cancer detection, it is simple, fast, cheap, not much invasive, and has a good efficacy.