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HelpTest ID AHUSC Atypical Hemolytic Uremic Syndrome (aHUS) Complement Panel, Serum and Plasma
Useful For
Detecting deficiencies in the alternative pathway that can cause atypical-hemolytic uremic syndrome, dense deposit disease, and C3 glomerulonephritis
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| INT51 | AHUSC Interpretation | No | Yes |
| AH50 | Complement, Alternate Path, Func, S | Yes | Yes |
| SC5B9 | SC5b-9 Complement, P | No | Yes |
| CBB | CBb Complement, P | No | Yes |
| C4D | C4d Complement, P | No | Yes |
| COM | Complement, Total, S | Yes | Yes |
| C3 | Complement C3, S | Yes | Yes |
| C4 | Complement C4, S | Yes | Yes |
| FBCA | Factor B Complement Antigen, S | No | Yes |
| FHCA | Factor H Complement Antigen, S | No | Yes |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| C1QFX | C1Q Complement, Functional, S | Yes | No |
| C2 | C2 Complement,Functional,w/Reflex,S | Yes | No |
| C3FX | C3 Complement, Functional, S | Yes | No |
| C4FX | C4 Complement, Functional, S | Yes | No |
| C5FX | C5 Complement, Functional, S | Yes | No |
| C6FX | C6 Complement, Functional, S | Yes | No |
| C7FX | C7 Complement, Functional, S | Yes | No |
| C8FX | C8 Complement, Functional, S | Yes | No |
| C9FX | C9 Complement, Functional, S | Yes | No |
Method Name
C3, C4, FBCA, FHCA: Nephelometry
COM: Automated Liposome Lysis Assay
AH50, C4D, CBB, SC5B9: Enzyme-Linked Immunosorbent Assay (ELISA)
Reporting Name
aHUS Complement Panel, S and PSpecimen Type
Plasma Na CitSerum
Serum Red
This test requires a minimum of 3 specimens:
-1 Frozen sodium citrate plasma specimen
-1 Frozen serum red top
-1 Refrigerated serum red top or serum gel
Specimen Type: Plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL
Collection Instructions:
1. Immediately after drawing the specimen, place the tube on wet ice.
2. Spin down and separate plasma from cells; 1,500 x g for 10 minutes at 4° C.
3. Remove plasma from cells and spin plasma a second time; 1,500 x g for 10 minutes at 4° C.
3. Freeze specimen immediately, within 4 hours.
Additional Information: Fasting preferred.
Specimen Type: Serum
Collection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL
Collection Instructions:
1. Immediately after drawing the specimen, place the tube on wet ice.
2. Spin down and separate serum from clot.
3. Immediately freeze specimen.
Additional Information: Fasting preferred.
Specimen Type: Serum
Collection Container/Tube: Red top or serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL
Collection Instructions:
1. Immediately after drawing the specimen, place the tube on wet ice.
2. Spin down and separate serum from clot.
3. Refrigerate
Additional Information: Fasting preferred.
Specimen Minimum Volume
Serum: 1 mL/Plasma: 1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
| Serum | Varies | 7 days |
| Serum Red | Frozen | 14 days |
Clinical Information
Individuals presenting with thrombotic microangiopathies (TMAs) require clinical testing to identify the underlying cause. Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are both acute syndromes with many overlapping clinical features. Reduced levels of ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motives) activity is associated with TTP and is one laboratory feature that distinguishes TTP from HUS. HUS can also have a number of causes; one of the rarer forms of disease is caused by defects in the alternative pathway of the complement system, so called atypical-HUS (aHUS). Patients with defective alternative pathway regulation can benefit from biologics that suppress the complement system. The purpose of this panel is to aid in the differential diagnosis of TMAs. The suggested approach is to rule out other causes of TMAs first, since aHUS is one of the rarer causes of TMAs.
Reference Values
FACTOR B COMPLEMENT ANTIGEN
15.2-42.3 mg/dL
SC5b-9 COMPLEMENT
≤250 ng/mL normal
FACTOR H COMPLEMENT ANTIGEN
23.6-43.1 mg/dL
C4d COMPLEMENT ACTIVATION FRAGMENT
≤9.8 mcg/mL
CBb COMPLEMENT ACTIVATION FRAGMENT
≤1.6 mcg/mL
COMPLEMENT C4
14-40 mg/dL
COMPLEMENT C3
75-175 mg/dL
COMPLEMENT, ALTERNATE PATHWAY (AH50), FUNCTIONAL
≥46% normal
COMPLEMENT, TOTAL
≥16 years: 30-75 U/mL
Reference values have not been established for patients who are <16 years of age.
Cautions
As with all complement assays, proper sample handling is of utmost importance to ensure that the complement system is not activated before clinical testing.
Samples should not be drawn earlier than 48 hours following plasma exchange.
If the purpose of testing is to determine defects in the complement pathway and the patient is on a C5 inhibitor, such as eculizumab (Soliris, Alexion Pharmaceuticals), the serum should be tested for the absence of C5 inhibitors. The recommended tests would be CH50, AH50, C5 Antigen (C5AG), and C5 functional (C5FX).
Day(s) Performed
Varies
Report Available
2 daysPerforming Laboratory
Mayo Medical Laboratories in Rochester
CPT Code Information
86160 x 7-Complement; antigen, each component
86161-functional activity, each component
86162-total hemolytic (CH50)