Impact of different storage times at room temperature of unspun citrated blood samples on routine coagulation tests results. Results of a bicenter study and review of the literature

Abstract

Summary Introduction A maximum delay between blood collection and coagulation testing of 4 hours is recommended by most guidelines. As information on optimal storage times is limited, we investigated the potential effect of different storage times of unspun tubes, that is, ≤2, 4, 6, and 8 hours, on routine coagulation test results. Methods Four evacuated polymer tubes containing 0.109 mol/L tri‐Na citrate were drawn from 144 patients, including 39 patients on vitamin K‐antagonists. Except for storage time, all tubes underwent the same preanalytical process. Prothrombin time (PT)/international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen, factor V (FV), FVIII, and D‐dimer were evaluated in two centers using the same technical conditions. Results Analytical comparison of aPTT, fibrinogen, FV, and FVIII results evaluated after prolonged storage times vs a <2‐hours storage demonstrated significant difference, whereas PT/INR and D‐dimer remained unchanged up to 8 hours. Mean bias between test results obtained after prolonged storage times remained below the desirable values for all studied parameters except for FVIII evaluated after 6‐ and 8‐hours storages, but only in patients with FVIII above 100 IU/dL. Even though the corresponding bias of −5.2% and −8.5%, respectively, remained within the GEHT recommended limits of variation, its evaluation after an 8‐hours storage could lead to significant underestimation of FVIII. Conclusion These results suggest that, in the studied technical conditions, PT/INR, aPTT, fibrinogen, FV, and D‐dimer can be reliably evaluated in tubes stored unspun at room temperature for up to 8 hours after blood collection. That optimal delay should be of 6 hours for FVIII.

Argatroban is stable in citrated whole blood for 24 hours

“…We have considered a difference of ± 0.10 μg/mL between fresh and stored samples as acceptable and also calculated percentage change in argatroban plasma level concentrations as acceptable stability from the baseline result as the in‐house reproducibility of HTI has CV's of 2.9%‐4.6%. However, discrepancy in the results is defined for this data as a test result that would have changed the therapeutic impact due to its storage induced change that is whole blood at room temperature for 24 hours this is in keeping with the recent paper by Toulon et al . Although statistically significant changes observed, these were not clinically relevant as the result would not have changed the patient's treatment.…”

Pre‐analytical stability of coagulation parameters in plasma stored at room temperature

“…We studied the stability of aliquoted plasma samples stored at RT for up to 48 hours. Several studies have investigated the stability of coagulation parameters, mainly routine haemostasis parameters, in different storage conditions; however, information regarding the stability of coagulation factors studied for up to 48 hours is scarce …”

“…[1][2][3][4] We studied the stability of aliquoted plasma samples stored at RT for up to 48 hours. Several studies have investigated the stability of coagulation parameters, mainly routine haemostasis parameters, in different storage conditions [7][8][9][10]13,16 ; however, information regarding the stability of coagulation factors studied for up to 48 hours is scarce. 6 According to our knowledge, no published guidelines, defining acceptable percentage changes for clinically relevant difference compared with baseline values, are available.…”

D-dimer: Preanalytical, analytical, postanalytical variables, and clinical applications

“…The use of a shorter centrifugation time will be indeed useful in emergency settings to reduce the TAT. The samples can be kept at room temperature for up to 8 h and at 4 C for up to 24 h (unspun citrated blood samples) before measurement of D-dimer [4,46,47]. Elf et al centrifuged blood samples at 4 C and measured D-dimer with two quantitative immunoassays (Innovance V R and AxSYM V R (Abbott, USA)) [48], although there was no evidence supporting cold centrifugation for D-dimer testing.…”

“…In brief, D-dimer is stable for at least 24 h (in plasma/whole blood) at room temperature (RT) or at 2-8 C with many different D-dimer immunoassays. Only B€ ohm-Weigert et al and Toulon et al suggested, respectively a 6-and 8-h D-dimer plasma stability, but this was because they did not extend their analysis for longer periods [47,69]. Frozen samples may also be used when longer storage periods (i.e.…”