Preliminary clinical evaluation of free/total PSA ratio by the IMMULITE system.
The role of free (F) and complexed serum PSA is now under investigation. In the present study, we evaluated the clinical significance of F-PSA and F/Total (T) PSA ratio in a preliminary series of samples from 88 patients with prostate cancer (PC), 113 with benign prostatic disease (BPD), and 98 with non-prostatic disease (NP). We used the F-PSA and third generation T-PSA (DPC, Los Angeles, USA) chemiluminescent enzyme immunometric assays with the IMMULITE automated system. At the 10 ng/ml cutoff for T-PSA levels, we obtained a sensitivity of 83% with a specificity of 100% in NP and 80% in BPD. The addition of the F/T ratio--rather than F-PSA levels--was useful to better discriminate PC and BPD in the cases erroneously classified by T-PSA alone: 44/68 samples (65%) were correctly diagnosed. Moreover, the F/T ratio was particularly effective in the critical T-PSA range between 4.1-9.9 ng/ml; 26/40 cases (65%) were correctly evaluated. In conclusion, the F/T ratio seems to be an interesting auxiliary test to T-PSA, to be reserved for selected cases where additional diagnostic information is necessary.
Correale
M
M
Clinical Chemistry Laboratory-RIA Unit, Oncology Institute, Bari, Italy.
Pagliarulo
A
A
Donatuti
G
G
Sturdà
F
F
Capobianco
A M
AM
Stigliani
V
V
Rizzello
M
M
Circhietta
S
S
Pignatelli
F
F
Leone
L
L
Frusciante
V
V
Modoni
S
S
Schittulli
F
F
D000368:Aged; D001331:Automation; D014408:Biomarkers, Tumor / Q000097:blood; D003937:Diagnosis, Differential; D006801:Humans; D007124:Immunoenzyme Techniques; D007558:Italy; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D017430:Prostate-Specific Antigen / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000097:blood* / Q000175:diagnosis; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen