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24903 Factor VIII Inhibitor Panel

Factor VIII Inhibitor Panel
Test Code: F8INHP
Synonyms/Keywords
​Inhibitor
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)​ ​ Two 0.75 mL  aliquots​ Two 0.75 mL  aliquots​ 0.75 mL​
Collection Processing Instructions

​Note: This is the recommended test for the initial demonstration of the presence of an inhibitor of factor VIII. A factor VIII will be performed and if the level is within the reference range, an inhibitor is not present and no further testing is indicated. In the event that the factor VIII level is below the lower limit of the reference range, an inhibitor assay will be performed to determine the strength of the inhibitor.

Two 0.75 mL citrated Blue Top Tube (BTT) plasma aliquots.
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%
-Tubes 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 fluids
​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 hoursModified APTT/optical clot detection/Siemens BCSXP​
​Monday through Friday​2-4 hoursBethesda assay/Siemens BCSXP​
Test Information
​Note: This is the recommended test for the initial demonstration of the presence of an inhibitor of factor VIII. A factor VIII will be performed and if the level is within the reference range, an inhibitor is not present and no further testing is indicated. In the event that the factor VIII level is below the lower limit of the reference range, an inhibitor assay will be performed to determine the strength of the inhibitor.
Reference Range Information
Performing Location Reference Range
​Marshfield

Factor 8 (VIII): 60-135% 

Factor VIII Inhibitor: 0.0 Bethesda Units​

Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​85240 ​ ​ Factor 8 (VIII) Activity Assay ​ ​
​85335 ​ ​ Factor Inhibitor​ Charge as needed​
Synonyms/Keywords
​Inhibitor
Ordering Applications
Ordering Application Description
​Centricity ​Factor VIII-Inhibitor Panel
​Cerner ​Factor VIII Inhibitor Panel
​COM ​Factor VIII Inhibitor Panel
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)​ ​ Two 0.75 mL  aliquots​ Two 0.75 mL  aliquots​ 0.75 mL​
Collection Processing

​Note: This is the recommended test for the initial demonstration of the presence of an inhibitor of factor VIII. A factor VIII will be performed and if the level is within the reference range, an inhibitor is not present and no further testing is indicated. In the event that the factor VIII level is below the lower limit of the reference range, an inhibitor assay will be performed to determine the strength of the inhibitor.

Two 0.75 mL citrated Blue Top Tube (BTT) plasma aliquots.
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%
-Tubes 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 fluids
​Specimens that thaw during storage or transport
Reference Range Information
Performing Location Reference Range
​Marshfield

Factor 8 (VIII): 60-135% 

Factor VIII Inhibitor: 0.0 Bethesda Units​

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Marshfield ​ ​Monday through Friday ​Less than 2 hoursModified APTT/optical clot detection/Siemens BCSXP​
​Monday through Friday​2-4 hoursBethesda assay/Siemens BCSXP​
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​85240 ​ ​ Factor 8 (VIII) Activity Assay ​ ​
​85335 ​ ​ Factor Inhibitor​ Charge as needed​
For most current information refer to the Marshfield Laboratory online reference manual.