Test Code LAB2782 Alternative Complement Pathway, Functional, Serum
Additional Codes
AH50
Reporting Name
Alternative Complement Path Func, SUseful For
Investigation of suspected alternative pathway complement deficiency, atypical hemolytic uremic syndrome, C3 glomerulonephritis, and dense-deposit disease
Ordering Guidance
COM / Complement, Total, Serum and this test are the most appropriate primary assays to use as screening methods for complement deficiencies. Abnormal results in one or the other, neither or both assays will help direct further testing.
This test is rarely useful when ordered in isolation.
Specimen Required
Patient Preparation: Patient should be fasting.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Immediately after specimen collection, place the tube on wet ice.
2. After sample has clotted on wet ice, centrifuge at 4° C and aliquot serum into a plastic vial.
3. Freeze specimen within 30 minutes of centrifugation. Sample must be placed on dry ice if not frozen immediately.
NOTE: If a refrigerated centrifuge is not available, it is acceptable to use a room temperature centrifuge, provided the specimen is kept on ice before centrifugation, and immediately afterward, the serum aliquoted and frozen.
Collect 2.0 mL whole blood in a Red top.
Specimen Type
Serum RedSpecimen Minimum Volume
0.2 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum Red | Frozen | 14 days |
Day(s) Performed
Monday, Thursday
TAT: 3 - 9 days
Performing Laboratory
Mayo Clinic Laboratories in RochesterMethod Name
Enzyme-Linked Immunosorbent Assay (ELISA)
Method Description
The Wieslab enzyme-linked immunosorbent assay complement assay for the alternative pathway combines principles of the hemolytic assay for complement activation with the use of labeled antibodies specific for neoantigens produced as a result of complement activation. The micro titer plate strips are coated with lipopolysaccharide. Patient serum is diluted in diluent containing specific blocker to ensure that only the alternative pathway is activated. During the first incubation, the diluted patient serum in the wells is activated by the coating. The wells are then washed and C5b-9 (membrane attack complex: MAC) is detected with a specific alkaline phosphatase labeled antibody to the neoantigen expressed during MAC formation. After a final wash, an alkaline phosphatase substrate is added. The amount of alternative pathway complement activity correlates with the color intensity of the solution and is measured in terms of absorbance (optical density).(Frazer-Abel A, Sepiashvili L, Mbughuni MM, Willrich MA. Overview of laboratory testing and clinical presentations of complement deficiencies and dysregulation. Adv Clin Chem. 2016;77:1-75. doi:10.1016/bs.acc.2016.06.001)
Reference Values
≥46% normal
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
86161
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
AH50 | Alternative Complement Path Func, S | 74520-8 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
88676 | Alternative Complement Path Func, S | 74520-8 |
Report Available
3 to 5 daysReject Due To
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.