Accurate filling of specimen tube essential.
Specimens must be transported at room temperature to the Laboratory in a red specimen bag ASAP. (Maximum delay to testing laboratory must not exceed 2hrs)
* * If several factor assays are requested e.g. II, V,VII and X, a total of 3 x sodium citrate tubes are required for an adult and 2 tubes for a child.

Factor VII has a biological half-life of 3-6 hours. In general, individuals with F VII levels < 10% of normal are more likely to exhibit haemorrhagic episodes than those with higher levels.  On rare occasions, the aPTT may be prolonged with F VII deficiency and is probably due to unique genetic defects in the F VII molecule. Warfarin use, Vit K deficiency, and liver disease are the main causes of acquired F VII deficiency. A few cases of thromboses have been described in congenitally F VII-deficient patients!