Test Details
Methodology
One-stage clotting, Nijmegen-modified Bethesda assay
Result Turnaround Time
3 - 8 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This assay is used to quantitate the titer of FVIII-specific inhibitors to porcine FVIII concentrate.
Limitations
Elevated levels of hemoglobin, bilirubin or lipids may interfere with this assay. Certain anticoagulant drugs (e.g. direct thrombin inhibitors, direct Xa inhibitors and/or heparin) or circulating anticoagulants (e.g. lupus anticoagulants) may lead to an erroneously low factor activity and erroneously positive specific factor inhibitor results.
Specimen Requirements
Specimen
Citrated plasma, frozen
Volume
1.5 mL
Minimum Volume
0.75 mL (Note: This volume does not allow for repeat testing)
Container
Blue-top (Sodium Citrate) tube
Collection Instructions
Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood-to- anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube. When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue -top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit seperate frozen specimens for each test requested.
Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Storage Instructions
Freeze
Patient Preparation
No special patient preparation is necessary.
Causes for Rejection
Thawed sample, wrong sample type
LOINC® Map
Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
---|---|---|---|---|---|---|
504474 | Porcine FVIII Nijmegen Beth | 504471 | Porcine FVIII Nijmegen Beth | BU/mL | 3204-5 | |
Order Code | 504474 | |||||
Order Code Name | Porcine FVIII Nijmegen Beth | |||||
Order Loinc | ||||||
Result Code | 504471 | |||||
Result Code Name | Porcine FVIII Nijmegen Beth | |||||
UofM | BU/mL | |||||
Result LOINC | 3204-5 |