Test Overview
Test Methodology

Photo-optical clot determination with Factor VIII deficient substrate.

Test Usage

Detection of specific coagulation factor VIII deficiency

Reference Range *

50-150%

Test Limitations
Test Details
Days Set Up
Daily, 24 hours for UMHS inpatients, Emergency Department patients, and Veterans Hospital patients. Monday-Friday, 1 run per day for MLabs and outpatients.
Analytic Time

2 hours

Soft Order Code
F8
MiChart Code
Factor 8 Assay
Synonyms
  • Coagulation Factor VIII Assay
  • Factor 8 Activity
  • Factor VIII Assay
  • Factor VIII:C Assay
  • F8
Laboratory
Hematopathology
Section
Coagulation
STAT Availability

STAT requests for this test will be performed on UMHS inpatients, Emergency Department patients, and Veterans Hospital patients.

Specimen Requirements
Collection Instructions

Collect specimen in a blue top (citrate 3.2%) tube. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Alternatively, centrifuge, aliquot plasma into a polypropylene plastic vial, and freeze the specimen within 4 hours of collection. Transport frozen specimen on dry ice. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device), the line should be flushed with 5 mL of saline and the first 5 mL of blood or six dead space volumes of the VAD discarded.

Rejection Criteria
Specimens will be rejected if not properly filled, clotted, grossly hemolyzed, or contaminated with heparin.
Contraindications
Test is not indicated if the patient is receiving heparin or direct thrombin inhibitor anticoagulation therapy. This test is not indicated for inpatient evaluation of acute thrombosis.
Blue Top Tube
Normal Volume
Full 2.7mL tube or 1mL plasma aliquot
Minimum Volume
Full 1.8mL tube or 1mL plasma aliquot
Storage Temperature
Room temperature for whole blood or frozen aliquot of citrated plasma.
Additional Information

Decreased factor VIII may be seen in association with: hemophilia, von Willebrand's disease, hypothyroidism, and disseminated intravascular coagulopathy. Factor VIII is an acute phase reactant; levels rise during strenuous exercise, periods of acute stress, following surgery, and in most inflammatory conditions. Factor VIII levels are also increased in pregnancy, carcinoma, leukemia, liver or renal disease, diabetes, deep vein thrombosis, and myocardial infarction.

Billing
CPT Code
85240
Fee Code
31127
LOINC
3209-4
NY State Approved
No