Intra-individual short-term variability of prostate-specific antigen and other kallikrein markers in a serial collection of blood from men under evaluation for prostate cancer Journal Article

   

Authors:	Christensson, A.; Bruun, L.; Björk, T.; Cronin, A. M.; Vickers, A. J.; Savage, C. J.; Lilja, H.
Article Title:	Intra-individual short-term variability of prostate-specific antigen and other kallikrein markers in a serial collection of blood from men under evaluation for prostate cancer
Abstract:	Objective To assess variation of total prostate-specific antigen (tPSA), free PSA (fPSA), percent fPSA, human glandular kallikrein 2 (hK2) and intact PSA measured three times within 2 weeks. Knowledge of the variation in an individual's PSA level is important for clinical decision-making. Patients and Methods Study participants were 149 patients referred for prostate biopsy, of which 97 had benign disease and 52 had prostate cancer. Three blood samples were drawn with a median of 4 h between first and second samples and 12 days between first and third samples. Variability was described by absolute differences, ratios and intra-individual coefficients of variation. Total PSA, fPSA, hK2 and intact PSA were measured in anticoagulated blood plasma. Results At baseline, the median tPSA was 6.8 (interquartile range, 4.5-9.6) ng/mL. The intra-individual variation was low for all biomarkers, and lowest for tPSA. For 80% of participants, the ratio between first and second time points for tPSA was in the range 0.91-1.09 and the ratio for percent fPSA was in the range 0.89-1.15. Total coefficients of variation between time 1 and 2 for tPSA, fPSA, percent fPSA, hK2 and intact PSA were 4.0%, 6.6%, 6.0%, 9.2% and 9.5%, respectively. The measurements taken several days apart varied more than those taken on the same day, although the variation between both time points was not large. Conclusions The intra-individual variation for all the kallikrein-like markers studied was relatively small, especially for samples drawn the same day. Few cases are reclassified between the time points. This indicates the high short-term biological and technical reproducibility of the tests in clinical use. © 2010 BJU INTERNATIONAL.
Keywords:	adult; controlled study; human tissue; aged; middle aged; unclassified drug; histopathology; cancer staging; neoplasm staging; prospective study; sensitivity and specificity; prostate specific antigen; protein blood level; cohort studies; observer variation; tumor markers, biological; cancer screening; time factors; prostate cancer; sweden; prostate-specific antigen; prostatic neoplasms; blood sampling; screening; biopsy, needle; antigen detection; psa; prostate biopsy; benign tumor; kallikrein related peptidase 2; kallikreins; free psa; tissue kallikrein; variation; antigenic variation
Journal Title:	BJU International
Volume:	107
Issue:	11
ISSN:	1464-4096
Publisher:	Wiley Blackwell
Date Published:	2011-06-01
Start Page:	1769
End Page:	1774
Language:	English
DOI:	10.1111/j.1464-410X.2010.09761.x
PROVIDER:	scopus
PUBMED:	20955263
PMCID:	PMC3572723
DOI/URL:	http://www.scopus.com/inward/record.url?eid=2-s2.0-79956369507&partnerID=40&md5=bca3ba68dbea8d45bd24194852e86823
Notes:	--- - "Export Date: 23 June 2011" - "CODEN: BJINF" - "Source: Scopus"

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