Testing is performed daily.

7 days refrigerated; up to 4 months frozen at -80°C.

Results obtained with different assay methods or kits cannot be used interchangeably.

An undetectable (<0.01 ng/mL) ultrasensitive prostate-specific antigen (USPSA) concentration after radical prostatectomy is reassuring and may aid in postoperative risk stratification of patients.
 
A detectable USPSA concentration (> or =0.01 ng/mL) after radical prostatectomy (RP) does not necessarily translate into disease progression or recurrence. Interpretation of a detectable USPSA needs to be made in conjunction with other clinicopathologic risk factors. The cutpoint for interpretation of USPSA assays remains controversial and has ranged from 0.01 to 0.05 ng/mL. For example, in a study that included 754 men after RP, a cutpoint of 0.01 ng/mL was an independent predictor of biochemical recurrence (BCR). BCR-free survival at 5 years was 92.4% for patients with an USPSA post-RP of less than 0.01 ng/mL and 56.8% for patients with an USPSA post-RP of 0.01 ng/mL or higher.(1) In the same study a cutoff of 0.03 ng/mL also predicted BCR independent of clinicopathological factors and BCR-free survival at 5 yrs was 90.8% for patients with an USPSA post-RP of less than 0.03 ng/mL and 26.9% for patients with a PSA post-RP of greater or equal to 0.03 ng/mL. (1)

1. Sokoll LJ, Zhang Z, Chan DW, et al. Do ultrasensitive prostate specific antigen measurements have a role in predicting long-term biochemical recurrence-free survival in men after radical prostatectomy? J Urol. 2016;195(2):330-336. doi:10.1016/j.juro.2015.08.080

Ultrasensitive Electrochemiluminescence Immunoassay (ECLIA)