Effects of pre-analytical storage time, temperature, and freeze-thaw times on coagulation factors activities in citrate-anticoagulated plasma

Abstract

Background: Coagulation factor assays are very important for diagnosing, treating, and monitoring inherited and acquired factor deficiencies. Appropriate pre-analytical storage conditions of citrate-anticoagulated plasma are essential for detection of coagulation factor activity. We aimed to investigate the effects of storage temperature and time on coagulation factor (F) II, FV, FVII, FX, FXI, and FXII activity up to 24 h and the effects of freeze-thaw times at -80 °C on factor activity.

Methods: Twenty-two blood samples were analyzed after storage for 0 (baseline), 2, 4, 6, 8, 12, and 24 h at 25 and 4 °C. Mean percent changes, numbers of samples with >10% changes, percent change trend plots, and difference plots were evaluated to determine clinically relevant differences.

Results: The acceptable storage times for FII coagulation activity (FII:C), FV:C, FVII:C, FX:C, FXI:C, and FXII:C were 24, 8, 8, 24, 12, and 12 h at 4 °C and 24, 4, 8, 8, 12, and 12 h at 25 °C, respectively. The acceptable freeze-thaw times for FII:C, FV:C, FVII:C, FX:C, FXI:C, and FXII:C were 2, 2, 3, 3, 2, and 1, respectively.

Conclusions: When factor activity cannot be determined within these acceptable timeframes, we recommend that plasma samples should be frozen and thawed at appropriate times for analysis.

Keywords: Coagulation factor; acceptable timeframes; freeze-thaw study; mean percent changes; storage temperature.

Figure 1

The flow chart of detection factors stabilities after storage for 0, 2, 4, 6, 8, 12, and 24 h at 25 or 4 °C.

Figure 2

The flow chart of detection factors stabilities after three freeze-thawing cycles at −80 °C.

Figure 3

Trend plots for mean percent changes in FII:C, FV:C, FVII:C, FX:C, FXI:C, and FXII:C in samples stored for 2, 4, 6, 8, 12, and 24 h at 4 and 25 °C. The two dotted lines show plus or minus 10% changes.

Figure 4

Freeze-thaw difference plots for FII:C, FV:C, FVII:C, FX:C, FXI:C, and FXII:C. ●: 1, percent changes in FII:C, FV:C, FVII:C, FX:C, FXI:C, and FXII:C after freeze-thawing one time; ■: 2, percent changes in FII:C, FV:C, FVII:C, FX:C, FXI:C, and FXII:C after freeze-thawing two times; ▲: 3, percent changes in FII:C, FV:C, FVII:C, FX:C, FXI:C, and FXII:C after freeze-thawing three times. The two dotted lines show plus or minus 10% changes.