[Comparison of Tandem-R PSA and Markit-M PA in the diagnosis of prostate cancer].
The Tandem-R PSA (TR) assay was compared with the Markit-M PA (MM) assay in the diagnosis of the prostate cancer. In patients with a serum prostate specific antigen (PSA) level higher than the cut-off values measured by either the TR assay or the MM assay (4.1 ng/ml and 3.7 ng/ml, respectively), or a suspicious digital rectal examination, sextant biopsy of the prostate was performed. Among 227 patients undergoing biopsy, 64 patients were diagnosed as having prostate cancer. There was a significant difference of serum PSA values between patients with and without prostate cancer in either assay. There was no significant difference between the assays with respect to diagnosing according to prostate cancer using receiver operating characteristic analysis. The correlation between TR and MM in 150 men with a serum Tandem-R PSA below 10 ng/ml was Y = 1.12X + 3.745 (R = 0.68, p < 0.001). The correlation coefficient for the relationship between TR and MM was only 0.68, indicating a poor correlation. Four of the 15 patients with MM values below 4.0 ng/ml calculated by transformation from MM to TR values had prostate cancer. This suggested that conversion of MM values to TR values in the low PSA range presents problems.
D000368:Aged; D005069:Evaluation Studies as Topic; D006801:Humans; D015592:Immunoradiometric Assay; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012680:Sensitivity and Specificity