What PSA analysis system does Quest use?

I am 15 months out from SBRT.
My PSA numbers have been steadily dropping.
For various reasons I have been tested by two different labs. I keep the numbers separate and do not really compare.
I just had my 15 month at one of the labs and found out they had changed from LabCorp to Quest. I will get those results tomorrow.
My question is does anyone know the system Quest uses?
LabCorp and the VA ( the labs I have been using ) both use the Roche Cobas analysis system.
No one at the clinic knew which system is used. They gave me a phone number but I am getting no answer and no call back so far.

Roger

Per Quest:

The total PSA value from this assay system is
standardized against the WHO standard. The test
result will be approximately 20% lower when compared
to the equimolar-standardized total PSA (Beckman
Coulter). Comparison of serial PSA results should be
interpreted with this fact in mind.

This test was performed using the Siemens
chemiluminescent method. Values obtained from
different assay methods cannot be used
interchangeably. PSA levels, regardless of
value, should not be interpreted as absolute
evidence of the presence or absence of disease.

It depends on which Quest lab it is sent to and which PSA test chosen. Quest has different codes for Total PSA and Ultrasensitive PSA (for post-prostatectomy). If you choose the Ultrasensitive PSA, the sample is usually sent to Quest's Lab in San Juan Capistrano, CA and that lab uses the Beckman Coulter DxI method. The regular PSA can be sent to one of many labs with different equipment, potentially the Siemens assay indicated by Bobby Mac above.

👍, or should that be👎! Going down is good. Congratulations!

Great news.