Test Overview
Method
Chromogenic Assay
Result Included
C1 Esterase Inhibitor - Functional
Aliases/Synonyms
C1 Inhibitor Functional
Specimen
Specimen Type
Plasma (Citrate)Containers
Collection Containers
Blue top (3.2% buffered citrate)
Volume
Sample Volume
1 mL
Collection & Handling
Collection Instructions
Separate plasma within 4 hours of collection.
Handling Information
Prepare platelet-poor plasma specimen and freeze immediately. Store and send frozen.
Stability
| Ambient | Frozen |
|---|---|
| 4 hours | > 4 hours at -70°C |
If the specimen thaws, it is unsuitable for analysis. This assay is very sensitive to sample handling and storage conditions.
Rejection Criteria
| Criteria | Specification |
|---|---|
| Specimen | Not frozen |
Performance & Interpretation
Turnaround Time
14 days
Results
-
C1 Esterase Inhibitor - FunctionalU/mL0.75 - 1.59
Comment
For assessment of angioedema correlate with other clinical features and with the results of quantitative levels of both C1 inhibitor protein and C4. This assay is very sensitive to sample handling and storage conditions. A repeat test (additional billing) with a fresh sample is recommended for results with borderline low/abnormal functional activity (0.69 - 0.74 U/mL).
Referral Location
Canada
Interface & Setup
HL7 Interface Codes
| Order Code | Result Name | Result Codes | Units |
|---|---|---|---|
| C1EFUN | C1-INHIBITOR | 62115 | U/mL |
Test Version
Last Updated
2023-03-21