C1 Esterase Functional Assay, Blood - Saskatoon
Discipline
Biochemistry
Overview
Description
- NOT the C1 Esterase inhibitor antigen testing
- Measurement of C1 esterase inhibitor functional assay should only be requested if C1 esterase inhibitor antigen is normal or elevated and clinical suspicion for hereditary angioedema remains high
- Specimen needs to be processed within required time frame
Alias
- C1 Esterase inhibitor, functional assay
- Functional C1-INH
- Functional C1 esterase
Specimen Information
Specimen types accepted
- Serum
Specimen collection container
- Preferred Collection Container: Red (no additive) 6.0mL
Collection procedure
- Specimen must be centrifuged, aliquoted and frozen within 60 minutes of collection
Required volume
- Optimal Volume: 5 mL Full collection tube
- Minimum Volume: 1 mL serum from full collection tube
(Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection.)
Transport and stability
- Store frozen.
- Ship to the referral lab on dry ice.
Rejection criteria
- Specimens received where the proper collection protocols were not followed
- Pathology and Laboratory Medicine Acceptance and Rejection Criteria
Testing Information
Clinical information
- Used in the diagnosis and monitoring of hereditary angioedema for monitoring response to therapy
- There are 2 types of hereditary angioedema that are distinguishable by biochemical testing. Patients with the common type, which account for 85% of the cases, have low levels of functional C1 inhibitor and C1 inhibitor antigen. Patients with the second form (15% of the cases) have low levels of functional C1 inhibitor but normal or increased levels of C1 inhibitor antigen.
Performance
Days/times performed
| Availability |
|
| Testing Site |
|
Maximum laboratory time
- 30 day turnaround time by testing laboratory
Other information
| Preferred Specimen Collection |
|
| Forms Required |
|
Last Updated: October 8, 2024