Third-generation PSA: ultrasensitive or ultraprecise assay?
The ultrasensitive PSA assay has been recently acknowledged as a useful tool for the monitoring of patients prostatectomized for prostatic cancer. We have evaluated a commercially available ultrasensitive PSA assay (Immulite Third Generation PSA-DPC-Los Angeles CA) in comparison with the routinely used PSA (Immulite PSA-DPC-Los Angeles CA). When evaluated with different approaches, the analytical sensitivity of ultrasensitive PSA ranged between 0.0029 and 0.0038 ng/ml. The biological detection limit was 0.0098 ng/ml. Dilution of samples with low PSA levels showed a good recovery (from 88 to 113%) up to 1:128 dilution factor (final PSA levels ranging from 0.004 to 0.016 ng/ml in different samples). The assay precision was excellent in the low dose range, the highest interassay interadjustment CV among replicates being 5.84% when assaying serum samples with PSA lower than 1.0 ng/ml. Besides its role in the follow-up of prostatectomized patients, the evaluated ultrasensitive PSA could be reliably used for the detection of clinically meaningful PSA variations in the low dose range, and it could therefore be a candidate for the assessment of PSA velocity.
Mione
R
R
Center for the Study of Biological Markers of Malignancy, National Center for the Application of Biotechnologies in Oncology, Venezia, Italy.
Barichello
M
M
Sartorello
P
P
Leon
A
A
Barioli
P
P
Gion
M
M
D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D011933:Reagent Kits, Diagnostic; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D011933:Reagent Kits, Diagnostic; D017430:Prostate-Specific Antigen