Menstuff® has compiled the following information on Complex
PSA Testing.
Background
What is cPSA?
How does cPSA work?
What are the unique benefits of
cPSA?
Where is the cPSA test available?
cPSA or Free PSA?
References
Total PSA (tPSA) is the most common PSA test used to detect CaP.
However, tPSA has low specificity leading to high levels of false
positives (indicating CaP was present when, in fact it was not) and
false negatives (indicating CaP was not present, in fact, it was). In
addition to expensive follow-up testing because of the high levels of
false positives associated with PSA, and the corresponding anxiety,
pain and inconvenience, research has focused on the development of
enhanced serum tests.
What are the unique benefits of cPSA?
Basic Math: Since tPSA is comprised of two basic components: cPSA (approximately 85% of total PSA in most cancer-free men) and fPSA (approximately 15% of total PSA in most cancer-free men) Bayer cPSA is a direct measure of the PSA form which is in greater proportion in men with CaP.1
Confidence: cPSA results will remain constant over time
under normal sample handling.3,4 The instability of fPSA can lead to
inaccurate measurement of the ratio of free to total PSA (f/t PSA)
and result in an increase in false-positive results.5
Where is the cPSA test available?
2 Okegawa, et. al, Comparison of two investigative assays for the complexed prostate specific antigen between 4.1 and 10.0 ng/mL. Urology. 2001;55(5): 700-704.
3 Allard, et. al, Multicenter evaluation of the performance and clinical utility in longitudinal monitoring of the Bayer Immuno 1 complexed PSA assay. Int J of Bio Markers. 1999;14(2): 73-83.
4 Jung, et. al, Different stability of free and complexed prostate specific antigen in serum in relation to specimen handling and storage conditions. Clin Chem Lab Med. 2000;38: 1271-1275.
5 Arcangeli, et al. Stability of serum total and free prostate specific antigen under varying storage intervals and temperatures. J of Urol. 1997;158: 2182-2187.
Source: www.pcaw.com/cPSA/index.asp
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