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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

  • Ruggero Dittadi , Aline S.C. Fabricio ORCID logo , Giulia Rainato , Edoardo Peroni , Fulvio Di Tonno , Beatrice Vezzù , Chiara Mazzariol , Elisa Squarcina , Laura Tammone and Massimo Gion ORCID logo EMAIL logo
Published/Copyright: September 15, 2018
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Clinical Chemistry and Laboratory Medicine (CCLM)
From the journal Clinical Chemistry and Laboratory Medicine (CCLM) Volume 57 Issue 4

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.

Keywords: [-2]proPSA; Phi; plasma; preanalytical phase; serum; stability
Corresponding author: Dr. Massimo Gion, MD, Centro Regionale Biomarcatori, AULSS3 Serenissima, Department of Clinical Pathology and Transfusion Medicine, SS Giovanni e Paolo Regional Hospital, Campo SS Giovanni e Paolo 6777, Ospedale Civile, 30122 Venezia, Italy, Phone: +390415294260, Fax: +390415294910

Acknowledgments

The authors are grateful to Prof. Ulf-Håkan Stenman (Helsinki University, Finland) for helpful discussion of results and valuable advice. We would like to thank Dr. Matelda Zancan for her support in preparing the study protocol; nurses of Endoscopy Ward for the collection of blood samples; Dr. Susanna Ferrarese and technicians of Laboratory Analysis Unit for the processing of blood samples. We are also grateful to Beckman Coulter (Brea, USA) for their kind unconditioned donation of assay kits of tPSA, fPSA and [-2]proPSA used in this study and to BD Diagnostics Preanalytical Systems – PAS (Milan, Italy) for their kind unconditioned donation of P100 tubes. We thank Dr. Antonette Leon for her contribution in editing the manuscript and Mrs. Ornella Scattolin for administrative assistance.

  1. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: This study was supported by Veneto Region (Italy) through the “Programma Regionale per I Biomarcatori Diagnostici, Prognostici e Predittivi” assigned to Azienda AULSS3 Serenissima; partially supported by the Italian Association for Research on Cancer Grant Special Program Molecular Clinical Oncology, 5×1000 (no. 12214) to M.G.; and also partially supported by Istituto Oncologico Veneto IOV – IRCCS, Padova, Italy and AVAPO Venezia Onlus, Venice, Italy.

  3. Employment or leadership: None declared.

  4. Honorarium: None declared.

  5. Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.

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Supplementary Material

The online version of this article offers supplementary material (https://doi.org/10.1515/cclm-2018-0596).

Received: 2018-06-08
Accepted: 2018-08-11
Published Online: 2018-09-15
Published in Print: 2019-03-26

©2019 Walter de Gruyter GmbH, Berlin/Boston

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https://doi.org/10.1515/cclm-2018-0596
Keywords for this article
[-2]proPSA; Phi; plasma; preanalytical phase; serum; stability

Articles in the same Issue

  1. Frontmatter
  2. Editorial
  3. Can Grail find the trail to early cancer detection?
  4. Reviews
  5. Aberrant glycosylation and cancer biomarker discovery: a promising and thorny journey
  6. Application of NMR metabolomics to search for human disease biomarkers in blood
  7. Mini Review
  8. Host-response biomarkers for the diagnosis of bacterial respiratory tract infections
  9. Opinion Paper
  10. Diabetes alert dogs: a narrative critical overview
  11. EFLM Paper
  12. Documenting metrological traceability as intended by ISO 15189:2012: A consensus statement about the practice of the implementation and auditing of this norm element
  13. General Clinical Chemistry and Laboratory Medicine
  14. Commutability of external quality assessment materials for serum sodium and potassium measurements
  15. Standardization of measurement procedures for serum uric acid: 8-year experience from Category 1 EQA program results in China
  16. Next-generation rapid serum tube technology using prothrombin activator coagulant: fast, high-quality serum from normal samples
  17. Cannabinoids determination in bronchoalveolar lavages of cannabis smokers with lung disease
  18. A new method for the determination of ammonium in the vitreous humour based on capillary electrophoresis and its preliminary application in thanatochemistry
  19. Reference Values and Biological Variations
  20. Defining reference intervals for a serum growth differentiation factor-15 (GDF-15) assay in a Caucasian population and its potential utility in diabetic kidney disease (DKD)
  21. Cancer Diagnostics
  22. Preanalytical stability of [-2]proPSA in whole blood stored at room temperature before separation of serum and plasma: implications to Phi determination
  23. Cardiovascular Diseases
  24. A de novo mutation of SMYD1 (p.F272L) is responsible for hypertrophic cardiomyopathy in a Chinese patient
  25. Infectious Diseases
  26. Analyzing the capability of PSP, PCT and sCD25 to support the diagnosis of infection in cancer patients with febrile neutropenia
  27. Mid-regional pro-adrenomedullin predicts poor outcome in non-selected patients admitted to an intensive care unit
  28. Validation of Mycobacterium tuberculosis real-time polymerase chain reaction for diagnosis of tuberculous meningitis using cerebrospinal fluid samples: a pilot study
  29. Letters to the Editor
  30. Methodological issues are important in cannabinoids determination in bronchoalveolar lavage
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  32. Letter to the Editor relating to Clin Chem Lab Med 2018;56(7):1090–1099
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