Israel Medical Association Journal

Background: The bladder tumor antigen stat is a simple and fast one-step immunochromatographic assay for the detection of bladder tumor-associated antigen in urine.

Objectives: To evaluate the BTA[1] stat in non-bladder cancer patients in order to identify the categories contributing to its low specificity.

Methods: A single voided urine sample was collected from 45 patients treated in the urology clinic for conditions not related to bladder cancer. Each urine sample was examined by BTA stat test and cytology.

Results: The overall specificity of the BTA stat test was 44%, which was significantly lower than that of urine cytology, 90%. The false positive rates for BTA stat test vary among the different clinical categories, being highest in cases of urinary tract calculi (90%), and benign prostatic hypertrophy (73%). Exclusion of these categories from data analysis improved BTA stat specificity to 66%.

Conclusions: Clinical categories contributing to low BTA stat specificity can be identified, and their exclusion improves the specificity of this test.

Background: The free-to-total prostate-specificantigen ratio is the best marker for optimizing prostate cancer detection. The main problem with studies of percent free PSA is the variability of reported cutoff values.

Objectives: To evaluate the influence of prostate size on the ratio of free to total PSA.

Methods: The study group included 58 patients (mean age 66.4 years) with clinically localized prostate cancer treated surgically at our institution. Total PSA and free PSA levels were measured by a solid phase enzyme immunoassay test (Hoffman-La Roche, Basel, Switzerland). The percent free PSA was compared with prostate size as determined from the surgical specimen.

Results: A direct relation was noted between prostate size and the percent free PSA value (r=0.49, P=0.0001). Mean percentage free PSA was 9%0.004 in men with normal-sized gland while in men with large prostate (60 g) the average percent free PSA was 15.90.09 (P=0.001).

Conclusions: In patients with prostate cancer the percent free PSA level is influenced by the gland size. The larger the prostate the higher the proportion of the free PSA. Such information may have influence on the recommendation for prostate biopsy in screening programs for early detection of prostate cancer.