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HelpTest Code Billings Clinic: 8412 Mayo: C1ES C1 Esterase Inhibitor Antigen, Serum
Reporting Name
C1 Esterase Inhibitor Antigen, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Diagnosis of hereditary angioedema
Monitoring levels of C1 esterase inhibitor in response to therapy
Method Name
Nephelometry
Specimen Required
Patient Preparations: Fasting preferred but not required.
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Immediately after specimen collection, place the tube on wet ice.
2. Centrifuge and aliquot serum into plastic vial.
3. Freeze specimen within 30 minutes.
Specimen Type
SerumSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 28 days | |
| Refrigerated | 28 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | Reject |
| Gross icterus | OK |
Reference Values
19-37 mg/dL
Interpretation
Abnormally low results are consistent with a heterozygous C1 esterase inhibitor deficiency and hereditary angioedema.
Fifteen percent of hereditary angioedema patients have a normal or elevated level but nonfunctional C1 esterase inhibitor protein. Detection of these patients requires a functional measurement of C1 esterase inhibitor; FC1EQ / C1 Esterase Inhibitor, Functional Assay, Serum.
Measurement of C1q antigen levels; C1Q / Complement C1q, Serum, is key to the differential diagnoses of acquired or hereditary angioedema. Those patients with the hereditary form of the disease will have normal levels of C1q, while those with the acquired form of the disease will have low levels.
Studies in children show that adult levels of C1 inhibitor are reached by 6 months of age.
Day(s) Performed
Monday through Friday
Report Available
2 to 5 daysTest Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
83883
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| C1ES | C1 Esterase Inhibitor Antigen, S | 4477-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| C1ES | C1 Esterase Inhibitor Antigen, S | 4477-6 |