1917 IN VITRO STABILITY OF FREE AND TOTAL PROSTATE SPECIFIC ANTIGEN IN SERUM VS EDTA PLASMA

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You have accessJournal of UrologyProstate Cancer: Detection and Screening1 Apr 20111917 IN VITRO STABILITY OF FREE AND TOTAL PROSTATE SPECIFIC ANTIGEN IN SERUM VS EDTA PLASMA Gyung-woo Jung, Sung Jin Park, and Jeong-woo Ye Gyung-woo JungGyung-woo Jung Busan, Korea, Republic of More articles by this author , Sung Jin ParkSung Jin Park Busan, Korea, Republic of More articles by this author , and Jeong-woo YeJeong-woo Ye Busan, Korea, Republic of More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.2055AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES In vitro instability of free and total prostate specific antigen (PSA) in blood samples might complicate the interpretation of the percent free PSA for the predictability of prostate cancer. The objective of this study was to directly compare the short-term stability of free and total PSA in serum and ethylenediaminetetraacetic acid (EDTA) plasma samples. METHODS Blood samples from 50 men were collected and processed to generate serum and EDTA plasma. Specimens were analyzed at baseline within 24 hours of collection and after 1 week of storage at 4 degrees C. Free PSA and total PSA were measured in all specimens. The changes in free PSA, total PSA and percent free PSA in serum and EDTA plasma with time were evaluated. Statistical analyses of the results were performed by paired t-test. RESULTS Concentrations of baseline total PSA in serum were not significantly different from those in EDTA plasma (4.83±0.45 ng/ml vs 4.81±0.44 ng/ml). In serum, however, baseline free PSA and percent free PSA were lower than in EDTA plasma (0.69±0.08 ng/ml, 14.58±0.81% vs 0.83±0.09 ng/ml, 17.89±0.93%; p<0.001). After 1 week, total PSA decreased slightly on average by 1.5% in serum and 1.1% in EDTA plasma, respectively. A decrease was seen in free PSA after 1 weak, with rates of 9.3% for serum and 3.9% for EDTA plasma. Similarly, there was a decrease in percent free PSA, with rates of 7.9% for serum and 2.7% for EDTA plasma. The decrease in percent free PSA in EDTA plasma was smaller than in serum significantly (p=0.003). CONCLUSIONS Free PSA is less stable with storage than total PSA in serum and EDTA plasma samples. In vitro stability of free PSA in EDTA plasma was less impaired than in serum. When using the percent free PSA in evaluation of patients with suspected prostate cancer, serum samples should be analyzed immediately after collection or EDTA plasma samples should be used. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e766-e767 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Gyung-woo Jung Busan, Korea, Republic of More articles by this author Sung Jin Park Busan, Korea, Republic of More articles by this author Jeong-woo Ye Busan, Korea, Republic of More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...