Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Factor VIII (also known as Anti-Haemophilic Factor (AHF)) is a non-vitamin K sensitive coagulation protein, synthesised primarily in the liver, but also in endothelial cells throughout the body. The gene for factor VIII is on the X chromosome and the disorder deficiency produces (Haemophilia A) is a recessive X-linked bleeding disorder. Factor VIII is a co-factor with Factor IX in the generation of Factor Xa. The PT is normal and the APTT is prolonged in cases of Factor VIII deficiency. Low levels are also seen in von Willebrand disease as the von Willeberand Factor acts as a carrier/protector protein for Factor VIII and a reduction in vWF results in a greatly reduced half life of Factor VIII.
Specimen container paediatric:
Light blue – sodium citrate
Specimen container adult:
Light blue – sodium citrate
Minimum volume paediatric:
1.3mL
Minimum volume adult:
2.7mL
Special requirements:
Tube must be correctly filled to line, to ensure correct ratio of blood to anticoagulant, ensure adequate mixing.
Sample stability:
4 hrs
Transport requirements:
Samples should be transported to lab without delay
Freq analysis:
As required or weekly
Add on test:
[email protected] (external)
Quality assurance:
UK NEQAS Blood Coagulation
Reference ranges:
50 – 150IU/dL Note: For Haemostatic tests, paediatric reference ranges may be different to adult ranges.
Other info:
A quantitative assay of coagulation factor VIII.
Urgent testing following approval by the on-call haemostasis consultant only.