Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Cold activation in PT-INR samples–Myth or reality in the modern laboratory?

Petersson, Annika LU ; Strandberg, Karin LU ; Magnusson, Magnus ; Lerman, Jenny and Ekblom, Kim (2025) In Scandinavian Journal of Clinical and Laboratory Investigation 85(3). p.175-179
Abstract

Guidelines on storage for samples intended for Prothrombin Time–International Normalized Ratio (PT-INR) analysis have changed over time, sometimes advising against cold storage due to presumed cold activation of the coagulation cascade. Previous studies on PT-INR storage have mainly been underpowered, performed in glass tubes, and not in a modern laboratory setting. In this study, we re-analyzed 1149 PT-INR samples, divided into low-level samples (PT-INR <1.3), and high-level samples (PT-INR 1.8–3.5) after 3 h of cold storage. We found no statistical difference for high-level samples but statistically higher PT-INR values in low-level samples. The differences were minor and not considered clinically relevant. No cold activation could... (More)

Guidelines on storage for samples intended for Prothrombin Time–International Normalized Ratio (PT-INR) analysis have changed over time, sometimes advising against cold storage due to presumed cold activation of the coagulation cascade. Previous studies on PT-INR storage have mainly been underpowered, performed in glass tubes, and not in a modern laboratory setting. In this study, we re-analyzed 1149 PT-INR samples, divided into low-level samples (PT-INR <1.3), and high-level samples (PT-INR 1.8–3.5) after 3 h of cold storage. We found no statistical difference for high-level samples but statistically higher PT-INR values in low-level samples. The differences were minor and not considered clinically relevant. No cold activation could be detected, as cold activation would have diminished PT-INR. These findings open the possibility of transporting and storing centrifuged PT-INR samples refrigerated. The higher PT-INR values in low-level samples after cold storage impede a mechanistic principle that needs to be further investigated.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
blood specimen collection, coagulation, Prothrombin time, refrigeration, specimen handling
in
Scandinavian Journal of Clinical and Laboratory Investigation
volume
85
issue
3
pages
5 pages
publisher
Informa Healthcare
external identifiers
  • scopus:105002590905
  • pmid:40183534
ISSN
0036-5513
DOI
10.1080/00365513.2025.2487972
language
English
LU publication?
yes
id
4477edd7-8206-4dde-8b1b-7867efba2cee
date added to LUP
2025-08-29 13:39:37
date last changed
2025-08-29 14:20:37
@article{4477edd7-8206-4dde-8b1b-7867efba2cee,
  abstract     = {{<p>Guidelines on storage for samples intended for Prothrombin Time–International Normalized Ratio (PT-INR) analysis have changed over time, sometimes advising against cold storage due to presumed cold activation of the coagulation cascade. Previous studies on PT-INR storage have mainly been underpowered, performed in glass tubes, and not in a modern laboratory setting. In this study, we re-analyzed 1149 PT-INR samples, divided into low-level samples (PT-INR &lt;1.3), and high-level samples (PT-INR 1.8–3.5) after 3 h of cold storage. We found no statistical difference for high-level samples but statistically higher PT-INR values in low-level samples. The differences were minor and not considered clinically relevant. No cold activation could be detected, as cold activation would have diminished PT-INR. These findings open the possibility of transporting and storing centrifuged PT-INR samples refrigerated. The higher PT-INR values in low-level samples after cold storage impede a mechanistic principle that needs to be further investigated.</p>}},
  author       = {{Petersson, Annika and Strandberg, Karin and Magnusson, Magnus and Lerman, Jenny and Ekblom, Kim}},
  issn         = {{0036-5513}},
  keywords     = {{blood specimen collection; coagulation; Prothrombin time; refrigeration; specimen handling}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{175--179}},
  publisher    = {{Informa Healthcare}},
  series       = {{Scandinavian Journal of Clinical and Laboratory Investigation}},
  title        = {{Cold activation in PT-INR samples–Myth or reality in the modern laboratory?}},
  url          = {{http://dx.doi.org/10.1080/00365513.2025.2487972}},
  doi          = {{10.1080/00365513.2025.2487972}},
  volume       = {{85}},
  year         = {{2025}},
}