Table 6 Summary of key pre-analytical recommendations about storage conditions

Storage conditions

Store samples at room temperature (15–25 °C) until analysis.

Perform whole blood assays <4 h after blood sampling and centrifugation <1 h.

Extremes of temperature (e.g. both refrigerated or high) should be avoided.

Store PPP at room temperature (15–25 °C) or at −80 °C until analysis.

If the whole blood sample is centrifuged within 1 h of collection, the plasma can be left on top of the cells at room temperature up to 4 h prior to testing.

Time from sampling to analysis depends on analyte:

Samples for PT/INR have longer stability (24 h) at room temperature.

Samples for aPTT should be performed using fresh plasma <4 h (<1 h in patients treated with unfractionated heparin).

For platelet function assays, samples should rest at room temperature for at least 15 min before analysis. Testing should be completed <3–4 h of collection.

For factors V and VIII analyses should be performed <3 h.

Fibrinogen, protein C and antithrombin activity appear to remain relatively constant when stored at room temperature for up to 7 days.

Protein S activity is unstable, with a statistically significant loss of activity at 8 h.

VWF appears to be stable at room temperature for 48 h.