Rapid detection of elevated prostate-specific antigen levels in blood: Performance of various membrane strip tests compared

Objectives. To compare the ability of four commercially available membrane strip tests to detect increased (4 mu g/L or more) concentrations of prosta te-specific antigen (PSA) in blood. Methods, Serum samples with PSA concentrations less than 4 mu g/L (n = 67) and from greater than 4 mu g/L to 20 mu g/L (n = 32) were independently exa mined by two observers using the PSA membrane strip tests from Chembio, Med pro, Seratec, and Syntron, The positive and negative results of each membra ne strip test were classified as either true positive or negative and false negative or positive by comparing them with the quantitative PSA assay of Immulite DPC using the conventional threshold value of 4 mu g/L. Results. The interobserver variations of the tests were between 93% and 97% . The color stability of the Seratec and Chembio tests did not show signifi cant differences between test results read within 10 to 20 minutes of the r eaction time; however, the results of the other two tests were especially a ffected by variations in the reading time. The sensitivity and specificity of the tests in relation to the threshold of 4 mu g/L were 67% to 93% and 8 7% to 97%, respectively. Conclusions. The Syntron test and, within certain limitations, the Seratec test fulfill the concept of a rapid and convenient PSA determination to det ect PSA concentrations greater than 4 mu g/L. Methodologic optimization of the tests by a grading of the PSA measuring ranges (eg, between 0 and 2, 3 and 4, 4 and 6, and 7 and 10 mu g/L) should be taken into account for futur e development. UROLOGY 53: 155-160, 1999. (C) 1999, Elsevier Science Inc. A ll rights reserved.