In addition, previous attempts to measure complexed PSA (PSA±ACT: PSA bound to a-1-antichymotrypsin) have been limited to the high cross reactivity of the monoclonal antibodies to other ACT
Circulating PSA can be divided into two main forms: complexed and free. Most circulating PSA is bound to a variety of protease inhi- bitors, most commonly a-1-antichymotrypsin, and the proportion of the total PSA concentration which is free or unbound is relatively small.
This finding has been exploited in the use of the ratio of free to total PSA and complexed PSA (cPSA) as a means of distinguishing between prostate cancer and BPH as a cause of an elevated PSA. (See 'Serum free and bound PSA' below and 'Complexed PSA' below.)
We selected serums from 51 fully characterized prostate cancer patients and 48 biopsy-proven BPH patients in order to test the ability of the ratio of the free/total PSA in distinguishing between CaP and BPH patients in the best case scenario. The 51 cancer patients had cancer volumes ranging from 2.0-17.8 mL and had a median % free PSA of 8.9%.
Correlation between the complex PSA/total PSA ratio and the free PSA/total PSA ratio, sensitivity and specificity of both markers for the diagnosis of prostate cancer Correlación del cociente PSA complex/PSA total con el cociente PSA libre/PSA total, sensibilidad y especificidad de ambos marcadores para el diagnóstico del cáncer de prostata☆
Results: The mean age of the entire population was 63.6 years (range 35 to 86). Abnormal digital rectal examination findings were present in 33.4% of the patients. The mean and median values of PSA and cPSA were significantly higher and the F/T PSA ratio was lower in patients with prostate cancer.
. 57 336 435 171 404 89 400 163
complexed psa vs free psa
