Alternative Complement Pathway, Functional, Serum
Use
The test is useful for investigating suspected alternative pathway complement deficiency, atypical hemolytic uremic syndrome, C3 glomerulonephritis, and dense-deposit disease. Functional testing of complement pathways is indicated for studying complement component deficiency and dysregulation, where it acts as a screening test for abnormalities in the alternative pathway. Systemic dysregulation can cause renal impairment or lead to diseases such as atypical hemolytic uremic syndrome and C3 glomerulopathies.
Special Instructions
This test should not be ordered in isolation but in combination with other tests such as COM / Complement, Total, Serum to help direct further testing. If a refrigerated centrifuge is not available during specimen preparation, it is acceptable to use a room temperature centrifuge provided the specimen is kept on ice before centrifugation and serum is aliquoted and frozen immediately afterward.
Limitations
Sample integrity is crucial as temperature degradation and complement component consumption can lead to false low function results, potentially confused with genuine dysregulation. Technical errors might be suspected if multiple components are low. Functional results that don't align with clinical history should be verified with a new blood draw. Optimal sample conditions are at -70 degrees Celsius or lower for long-term stability, and samples should be frozen immediately post-collection.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 74520-8
- 74520-8
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.75 mL
Container
Plastic vial
Collection Instructions
Immediately after specimen collection, place the tube on wet ice and allow it to clot. Centrifuge at 4 degrees C and aliquot serum into a plastic vial. Freeze specimen within 30 minutes of centrifugation. Specimen must be placed on dry ice if not frozen immediately. If a refrigerated centrifuge is unavailable, a room temperature centrifuge may be used provided the specimen is kept on ice before centrifugation, and immediately afterward, the serum aliquoted and frozen.
Patient Preparation
Fasting for 8 hours is preferred but not required.
Storage Instructions
Specimens should be frozen immediately after collection.
Causes for Rejection
Gross hemolysis, lipemia, icterus are acceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |