Factor VIII (8) Assay | KK Women's and Children's Hospital

Specimen Container

3.2% Sodium Citrate Tube

Specimen Requirement

Citrated Whole Blood

Adult: 2 mL

Paediatric and Neonate: 1 ml

- Gently invert the tubes several times to prevent clotting. Clotted specimen is not suitable for testing.

- To collect blood to the designate marking. Over or under filling will compromise the test results.

- When using a winged blood collection set for venipuncture and a coagulation tube is the first tube drawn, draw a discard tube first.

- When obtaining specimens from indwelling lines that may contain heparin, the line should be flushed with 5mL of saline; and the first 5mL of blood or 6-times the line volume (dead space volume of the catheter) be drawn off and discarded before the coagulation tube is filled.

- For those samples collected from a normal saline lock (capped off venous port) twice the dead space volume of the catheter and extension set should be discarded.

Specimen Storage/Transport

Send to laboratory as soon as possible after blood collection. Do not send in ice.

Orderable as Urgent?

Turn Around Time

5 days

Urgent tests requiring a shorter turnaround time can be requested by contacting the laboratory haematologist-on-call.

Reference Value(s)

Age Group	Gender	Reference Intervals (%)
Day 0-2	Both	105 - 329
Day 3 - 30	Both	83 - 274
1 Month - 1 Year	Both	54 - 145
1 - 5 Year	Both	36 - 185
6 - 10 Years	Both	52 - 182
11 - 16 Years	Both	59 - 200
Adults (above 16 Years)	Both	52 - 290
Adopted from Royal Children's Hospital, Melbourne, Australia.

Testing Laboratory Location

KKH

Laboratory

Haematology

Contact Number

6394 1373

Day and Time Performed

Wednesday (1300 hrs - 1700Hrs)
Friday (1300 hrs - 1700 hrs)

Orderable on CPOE?

Yes

Downtime Form

63170-Form-1080 Haematology Laboratory Downtime Form

Additional Information

Approval from Haematologist is required for test request after operating hours.

This is a Clot-based Factor VIII assay.

For patients on HEMLIBRA® (Emicizumab), please order for Chromogenic FVIII.

Change History Notes

16 Sep 2024 08:00 AM

Updated Specimen Container, Orderable as STAT?, Turn Around Time, Additional Information.
06 Feb 2023 12:00 AM

Updated Specimen Storage / Transport, Laboratory, Downtime Form, Additional Information.
21 Oct 2022 12:00 AM

Updated Specimen Requirement, Specimen Storage / Transport.
12 May 2022 12:00 AM

Test effective on 30/3/2022.

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Last Updated - 05 Apr 2025