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22450 Factor Assay-8 (VIII)

Factor Assay-8 (VIII)
Test Code: F-VIII
Synonyms/Keywords
​Factor VIII Activity, AHF, FVIII
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
*Platelet Poor Plasma 3.2% Citrated Blue Top Tube (BTT)​Citrated Blue Top Tube (BTT)​ ​ 0.75 mL ​ 0.75 mL ​ 0.5 mL​
Collection Processing Instructions
​One 0.75 mL citrated Blue Top Tube (BTT) plasma aliquot.
If more than one coagulation test is ordered, a separate aliquot is needed for each test.
-Collect in Citrated Blue Top Tube (BTT)
-Citrate anticoagulant must be adjusted for HCT >55%
-Tube must be at least 90% full
-Invert completely 3-4 times (without shaking) to mix
*See Instructions for: Preparation of Platelet Poor Plasma
Specimen Stability Information
Specimen Type Temperature Time
​Plasma ​Frozen ​6 months
Rejection Criteria
Clotted or Hemolyzed
​Contamination with IV or Hickman Line fluid
​Specimens that thaw during storage or transport
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Marshfield ​Monday through Friday ​Less than 2 hours Modified APTT/optical clot detection/Siemens BCSXP​
Reference Range Information
Performing Location Reference Range
​Marshfield ​60-135% of normal activity
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​85240 ​ ​ ​ ​
Synonyms/Keywords
​Factor VIII Activity, AHF, FVIII
Ordering Applications
Ordering Application Description
​Centricity ​Factor-VIII
​Cerner ​Factor VIII Assay
​COM ​Factor Assay-8 (VIII)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
*Platelet Poor Plasma 3.2% Citrated Blue Top Tube (BTT)​Citrated Blue Top Tube (BTT)​ ​ 0.75 mL ​ 0.75 mL ​ 0.5 mL​
Collection Processing
​One 0.75 mL citrated Blue Top Tube (BTT) plasma aliquot.
If more than one coagulation test is ordered, a separate aliquot is needed for each test.
-Collect in Citrated Blue Top Tube (BTT)
-Citrate anticoagulant must be adjusted for HCT >55%
-Tube must be at least 90% full
-Invert completely 3-4 times (without shaking) to mix
*See Instructions for: Preparation of Platelet Poor Plasma
Specimen Stability Information
Specimen Type Temperature Time
​Plasma ​Frozen ​6 months
Rejection Criteria
Clotted or Hemolyzed
​Contamination with IV or Hickman Line fluid
​Specimens that thaw during storage or transport
Reference Range Information
Performing Location Reference Range
​Marshfield ​60-135% of normal activity
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Marshfield ​Monday through Friday ​Less than 2 hours Modified APTT/optical clot detection/Siemens BCSXP​
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​85240 ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.