C1 Esterase Inhibitor, Functional

C1 Esterase Inhibitor, Functional

Test Code

297
86161
297
86161
Not offered in Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection is not available in your area through Quest Mobile.

Clinical Significance

C1 Esterase Inhibitor, Functional - 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.

Test Resources

Test FAQ

C1 Inhibitor, Protein and Functional Tests

Test Details

Methodology

Enzyme Immunoassay (EIA)

Reference Range(s)

≥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.

Alternative Name(s)

C1 Inactivator,C1 Inhibitor, Functional

LOINC® Codes, Performing Laboratory

Service Area must be determined

Methodology

Enzyme Immunoassay (EIA)

Reference Range(s)

≥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.

Alternative Name(s)

C1 Inactivator,C1 Inhibitor, Functional
Service Area must be determined

Preferred Specimen(s)

1 mL frozen serum collected in a red-top tube (no gel)

Minimum Volume

0.2 mL

Collection Instructions

Freeze serum within 1 hour of time drawn.
Do not use gel barrier tubes. Do not submit the sample in a glass tube. Do not thaw.

Transport Container

Transport tube

Transport Temperature

Frozen

Specimen Stability

  • Room temperature: Unacceptable
  • Refrigerated: Unacceptable
  • Frozen: 30 days

Reject Criteria

Grossly lipemic • Serum separator tube (SST) • Received thawed

Setup Schedule

Service Area must be determined
1 mL frozen serum collected in a red-top tube (no gel)
0.2 mL
Freeze serum within 1 hour of time drawn.
Do not use gel barrier tubes. Do not submit the sample in a glass tube. Do not thaw.
Transport tube
Frozen
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days
Grossly lipemic • Serum separator tube (SST) • Received thawed
Service Area must be determined
Not offered in Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection is not available in your area through Quest Mobile.
Test Details

Clinical Significance

Test Resources

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.

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