C1 Esterase Inhibitor, Functional
Test Summary
C1 esterase is decreased in angioedema. The inherited form is usually diagnosed in the first two decades of life. The acquired form affects primarily adults with autoimmune or lymphoproliferative disorders. Approximately 15% of patients with hereditary angioedema have a normal concentration of the protein but it is dysfunctional.
Aliases
- N/A
Specimen Collection
Special Instructions
N/A
Preferred Specimen
1 mL serum collected in a red-top tube (no gel)
Minimum Volume
0.2 mL
Instructions
Freeze serum within one hour of time drawn.
Do not submit the sample in a glass tube. Do not thaw.
Do not submit the sample in a glass tube. Do not thaw.
Patient Preparation
N/A
Storage
N/A
Transport Temperature
Frozen
Specimen Stability
- Room temperature: Unacceptable
- Refrigerated: Unacceptable
- Frozen: 30 days
Limitations
N/A
Other Acceptable Specimens
N/A
Unacceptable Specimens
Grossly lipemic • Serum separator tube (SST) • Received thawed
Order Code
C1ESTF
EPIC (Premier) Code
LAB6155
Includes
N/A
CPT Code
- 86161
Billing Code
- 670607
CPT Statement
Methodology
Enzyme Immunoassay (EIA)
FDA Status
FDA Approved
Physician Attestation of Informed Consent
N/A
Testing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly VA, 20153
14225 Newbrook Drive
Chantilly VA, 20153
Department
Reference Testing
Reference Range
| ≥68 % | Normal |
| 41-67 % | Equivocal |
| ≤40 % | Abnormal |
Less than 40% of the reference functional activity indicates a likely diagnosis of hereditary angioedema or acquired C1 Inhibitor deficiency.
Setup Schedule / Expected Turnaround Time
Monday - Saturday afternoon Report available: 1 day
Specimen Collection
Special Instructions
N/A
Preferred Specimen
1 mL serum collected in a red-top tube (no gel)
Minimum Volume
0.2 mL
Instructions
Freeze serum within one hour of time drawn.
Do not submit the sample in a glass tube. Do not thaw.
Do not submit the sample in a glass tube. Do not thaw.
Patient Preparation
N/A
Storage
N/A
Transport Temperature
Frozen
Specimen Stability
- Room temperature: Unacceptable
- Refrigerated: Unacceptable
- Frozen: 30 days
Limitations
N/A
Other Acceptable Specimens
N/A
Unacceptable Specimens
Grossly lipemic • Serum separator tube (SST) • Received thawed
Result Information
Methodology
Enzyme Immunoassay (EIA)
Testing Laboratory
N/A
Reference Range
| ≥68 % | Normal |
| 41-67 % | Equivocal |
| ≤40 % | Abnormal |
Less than 40% of the reference functional activity indicates a likely diagnosis of hereditary angioedema or acquired C1 Inhibitor deficiency.
Setup Schedule / Expected Turnaround Time
Monday - Saturday afternoon Report available: 1 day