I reported a TPSA OF 7.2 ng/ml, with a Free PSA of >25. The 1 in 5 diln gave
the TPSA of 7 approx when multiplied up and the Free PSA gave 35 when
multiplied up (and not >25 which I incorrectly stated) using Immulite 2000.
We have assayed the sample with the Wallac system, and the TPSA is 93 ng/ml,
with a Free PSA of 35.6. It has been suggested thanks to this mailbase that
our patient has a deletion in the PSA which the Immulite antibody is not
recognising, and the levels obtained with our old Wallac system seem to
support this. What is surprising is that we are only using the DPC Immulite
about 2-3 months, so is this deletion more common than thought previously?.
Thanks to all those who responded and even gave me the references to a
previous report Clin Chem 42:4 637-641 1996
Dr Helen Grimes
Department of Clinical Biochemistry
University College Hospital
Galway
Ireland
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