Preanalytical stability of [-2]proPSA in whole blood stored at room temperature before separation of serum and plasma

implications to Phi determination

Ruggero Dittadi, Aline S C Fabricio, Giulia Rainato, Edoardo Peroni, Fulvio Di Tonno, Beatrice Vezzù, Chiara Mazzariol, Elisa Squarcina, Laura Tammone, Massimo Gion

Research output: Contribution to journalArticle

Abstract

Background [-2]proPSA seems to outperform free/total prostate-specific antigen (PSA) ratio in prostate cancer diagnosis. However, [-2]proPSA stability remains an underestimated issue. We examined [-2]proPSA stability over time in whole blood before separation of serum and plasma and its implications for prostate health index (Phi) determination. Total PSA (tPSA) and free PSA (fPSA) stabilities were also assessed. Methods Blood was drawn from 26 patients and separated in two tubes for plasma (K2EDTA and K2EDTA plus protease inhibitors - P100) and one for serum (clot activator plus gel separator). Tubes were stored at room temperature before centrifugation 1, 3 and 5 h for serum and EDTA plasma or 1 and 5 h for P100 plasma. To investigate the influence of gel separator on markers' stability, blood was collected from 10 patients in three types of tubes to obtain serum: tubes with clot activator plus gel separator, with silica particles or glass tubes. Biomarkers were assayed with chemiluminescent immunoassays. Results [-2]proPSA and Phi levels significantly and progressively increased over time in serum (+4.81% and +8.2% at 3 h; +12.03% and +14.91% at 5 h, respectively, vs. 1 h; p<0.001). Conversely, [-2]proPSA levels did not change in plasma (EDTA or P100). tPSA levels did not change over time in serum or plasma, whereas fPSA decreased in serum. All markers were higher in plasma than in serum at any time point. This difference did not seem to be attributable to the use of gel for serum preparation. Conclusions EDTA prevented spurious in vitro modifications in PSA-related isoforms, confirming that a stabilized blood sample is a prerequisite for [-2]proPSA measurement and Phi determination.

Original languageEnglish
JournalClinical Chemistry and Laboratory Medicine
DOIs
Publication statusE-pub ahead of print - Sep 15 2018

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Prostate
Blood
Health
Plasmas
Temperature
Prostate-Specific Antigen
Serum
Separators
Gels
Edetic Acid
Centrifugation
Biomarkers
Protease Inhibitors
Silicon Dioxide
Protein Isoforms
Immunoassay
Health Status
Glass
Prostatic Neoplasms

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Preanalytical stability of [-2]proPSA in whole blood stored at room temperature before separation of serum and plasma : implications to Phi determination. / Dittadi, Ruggero; Fabricio, Aline S C; Rainato, Giulia; Peroni, Edoardo; Di Tonno, Fulvio; Vezzù, Beatrice; Mazzariol, Chiara; Squarcina, Elisa; Tammone, Laura; Gion, Massimo.

In: Clinical Chemistry and Laboratory Medicine, 15.09.2018.

Research output: Contribution to journalArticle

Dittadi, Ruggero ; Fabricio, Aline S C ; Rainato, Giulia ; Peroni, Edoardo ; Di Tonno, Fulvio ; Vezzù, Beatrice ; Mazzariol, Chiara ; Squarcina, Elisa ; Tammone, Laura ; Gion, Massimo. / Preanalytical stability of [-2]proPSA in whole blood stored at room temperature before separation of serum and plasma : implications to Phi determination. In: Clinical Chemistry and Laboratory Medicine. 2018.
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abstract = "Background [-2]proPSA seems to outperform free/total prostate-specific antigen (PSA) ratio in prostate cancer diagnosis. However, [-2]proPSA stability remains an underestimated issue. We examined [-2]proPSA stability over time in whole blood before separation of serum and plasma and its implications for prostate health index (Phi) determination. Total PSA (tPSA) and free PSA (fPSA) stabilities were also assessed. Methods Blood was drawn from 26 patients and separated in two tubes for plasma (K2EDTA and K2EDTA plus protease inhibitors - P100) and one for serum (clot activator plus gel separator). Tubes were stored at room temperature before centrifugation 1, 3 and 5 h for serum and EDTA plasma or 1 and 5 h for P100 plasma. To investigate the influence of gel separator on markers' stability, blood was collected from 10 patients in three types of tubes to obtain serum: tubes with clot activator plus gel separator, with silica particles or glass tubes. Biomarkers were assayed with chemiluminescent immunoassays. Results [-2]proPSA and Phi levels significantly and progressively increased over time in serum (+4.81{\%} and +8.2{\%} at 3 h; +12.03{\%} and +14.91{\%} at 5 h, respectively, vs. 1 h; p<0.001). Conversely, [-2]proPSA levels did not change in plasma (EDTA or P100). tPSA levels did not change over time in serum or plasma, whereas fPSA decreased in serum. All markers were higher in plasma than in serum at any time point. This difference did not seem to be attributable to the use of gel for serum preparation. Conclusions EDTA prevented spurious in vitro modifications in PSA-related isoforms, confirming that a stabilized blood sample is a prerequisite for [-2]proPSA measurement and Phi determination.",
author = "Ruggero Dittadi and Fabricio, {Aline S C} and Giulia Rainato and Edoardo Peroni and {Di Tonno}, Fulvio and Beatrice Vezz{\`u} and Chiara Mazzariol and Elisa Squarcina and Laura Tammone and Massimo Gion",
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T1 - Preanalytical stability of [-2]proPSA in whole blood stored at room temperature before separation of serum and plasma

T2 - implications to Phi determination

AU - Dittadi, Ruggero

AU - Fabricio, Aline S C

AU - Rainato, Giulia

AU - Peroni, Edoardo

AU - Di Tonno, Fulvio

AU - Vezzù, Beatrice

AU - Mazzariol, Chiara

AU - Squarcina, Elisa

AU - Tammone, Laura

AU - Gion, Massimo

PY - 2018/9/15

Y1 - 2018/9/15

N2 - Background [-2]proPSA seems to outperform free/total prostate-specific antigen (PSA) ratio in prostate cancer diagnosis. However, [-2]proPSA stability remains an underestimated issue. We examined [-2]proPSA stability over time in whole blood before separation of serum and plasma and its implications for prostate health index (Phi) determination. Total PSA (tPSA) and free PSA (fPSA) stabilities were also assessed. Methods Blood was drawn from 26 patients and separated in two tubes for plasma (K2EDTA and K2EDTA plus protease inhibitors - P100) and one for serum (clot activator plus gel separator). Tubes were stored at room temperature before centrifugation 1, 3 and 5 h for serum and EDTA plasma or 1 and 5 h for P100 plasma. To investigate the influence of gel separator on markers' stability, blood was collected from 10 patients in three types of tubes to obtain serum: tubes with clot activator plus gel separator, with silica particles or glass tubes. Biomarkers were assayed with chemiluminescent immunoassays. Results [-2]proPSA and Phi levels significantly and progressively increased over time in serum (+4.81% and +8.2% at 3 h; +12.03% and +14.91% at 5 h, respectively, vs. 1 h; p<0.001). Conversely, [-2]proPSA levels did not change in plasma (EDTA or P100). tPSA levels did not change over time in serum or plasma, whereas fPSA decreased in serum. All markers were higher in plasma than in serum at any time point. This difference did not seem to be attributable to the use of gel for serum preparation. Conclusions EDTA prevented spurious in vitro modifications in PSA-related isoforms, confirming that a stabilized blood sample is a prerequisite for [-2]proPSA measurement and Phi determination.

AB - Background [-2]proPSA seems to outperform free/total prostate-specific antigen (PSA) ratio in prostate cancer diagnosis. However, [-2]proPSA stability remains an underestimated issue. We examined [-2]proPSA stability over time in whole blood before separation of serum and plasma and its implications for prostate health index (Phi) determination. Total PSA (tPSA) and free PSA (fPSA) stabilities were also assessed. Methods Blood was drawn from 26 patients and separated in two tubes for plasma (K2EDTA and K2EDTA plus protease inhibitors - P100) and one for serum (clot activator plus gel separator). Tubes were stored at room temperature before centrifugation 1, 3 and 5 h for serum and EDTA plasma or 1 and 5 h for P100 plasma. To investigate the influence of gel separator on markers' stability, blood was collected from 10 patients in three types of tubes to obtain serum: tubes with clot activator plus gel separator, with silica particles or glass tubes. Biomarkers were assayed with chemiluminescent immunoassays. Results [-2]proPSA and Phi levels significantly and progressively increased over time in serum (+4.81% and +8.2% at 3 h; +12.03% and +14.91% at 5 h, respectively, vs. 1 h; p<0.001). Conversely, [-2]proPSA levels did not change in plasma (EDTA or P100). tPSA levels did not change over time in serum or plasma, whereas fPSA decreased in serum. All markers were higher in plasma than in serum at any time point. This difference did not seem to be attributable to the use of gel for serum preparation. Conclusions EDTA prevented spurious in vitro modifications in PSA-related isoforms, confirming that a stabilized blood sample is a prerequisite for [-2]proPSA measurement and Phi determination.

U2 - 10.1515/cclm-2018-0596

DO - 10.1515/cclm-2018-0596

M3 - Article

JO - Clinical Chemistry and Laboratory Medicine

JF - Clinical Chemistry and Laboratory Medicine

SN - 1434-6621

ER -