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Test Code MISC2MAYOECUMP Eculizumab Monitoring Panel, Serum

Secondary ID


Useful For

Therapeutic drug monitoring of eculizumab

Profile Information

Test ID Reporting Name Available Separately Always Performed
C5FX C5 Complement, Functional, S Yes Yes
C5AG2 C5 Complement, Antigen, S Yes, (Order C5AG) Yes
INT86 ECUMP Interpretation No Yes

Method Name

C5AG2: Nephelometry

C5FX: Automated Liposome Lysis Assay

Reporting Name

Eculizumab Monitoring Panel, S

Specimen Type

Serum Red

Specimen Required

Patient Preparation: Fasting preferred

Supplies: Aliquot Tube, 5 mL (T465)

Specimen Type: Serum

Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions:

1. Recommended timeframe for the blood collection is a trough, or immediately prior to next intravenous infusion.

2. Immediately after specimen collection, place the tube on wet ice.

3. Centrifuge and aliquot serum into plastic vial.

4. Freeze specimen within 30 minutes.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Frozen 14 days

Reject Due To

Gross hemolysis OK
Gross lipemia Reject
Gross icterus OK

Clinical Information

Eculizumab (Soliris, Alexion Pharmaceuticals) is a humanized hybrid monoclonal antibody (IgG2/IgG4) that blocks complement C5 cleavage, thereby preventing the activation of the proinflammatory effects of C5a and the cytolytic effects of the membrane attack complex (MAC) formed by C5b-C9. It is US Food and Drug Administration approved for atypical hemolytic uremic syndrome(1) and paroxysmal nocturnal hemoglobinuria,(2) and it is also prescribed for other conditions such as C3 glomerulopathies.(3) The dosing regimen for an average adult may vary from 300 to 1200 mg intravenously every 2 weeks during the maintenance stages, according to the condition for which the drug is prescribed. Therapy efficacy may be monitored by measuring efficiency of complement blockade.(4) Eculizumab will affect complement function assays that rely on the formation of the MAC to generate cell lysis. Although total complement and soluble MAC have been recommended for eculizumab monitoring, the measurement of C5 function and C5 antigen more specifically indicate the impact of eculizumab on the complement system blockage and may help guide the next dose of the drug.


This panel measures the pharmacodynamics effects of eculizumab on the complement system.

Reference Values


10.6-26.3 mg/dL



29-53 U/mL


The panel will measure the pharmacodynamic effects of eculizumab on the complement system. Total complement function, alternative pathway function, and C5 function assays will be decreased to a similar extent in the presence of eculizumab. The function of C5 may be completely absent when eculizumab is present at therapeutic concentrations. C5 antigen, on the other hand, will be normal or elevated. C5 complement function drops on average 30% with 25 mcg/mL of eculizumab, and 70% with 50 mcg/mL. In the presence of 100 mcg/mL of eculizumab in serum, there is on average 20% residual C5 function.


Decreased C5 function in the presence of normal or elevated C5 antigen concentrations suggests eculizumab is partially blocking C5 activity.


Absent C5 function in the presence of normal or elevated C5 antigen concentrations suggests eculizumab is completely blocking C5 activity.


Normal C5 function in the presence of normal or elevated C5 antigen concentrations suggests eculizumab concentration is not sufficient to block C5 activity.


If C5 function and C5 antigen concentrations are all decreased, it may be due to a secondary consumption process, poor hepatic synthesis of complement proteins or C5 deficiency. Clinical correlation recommended. If indicated, resubmit samples to confirm results.

Day(s) Performed

Monday through Friday

Report Available

2 to 14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information



LOINC Code Information

Test ID Test Order Name Order LOINC Value
ECUMP Eculizumab Monitoring Panel, S In Process


Result ID Test Result Name Result LOINC Value
C5FX C5 Complement, Functional, S 60472-8
C5AG2 C5 Complement, Antigen, S 4505-4
INT86 ECUMP Interpretation 69048-7


If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Renal Diagnostics Test Request (T830)

-Coagulation Test Request (T753)

-Therapeutics Test Request (T831)

Method Description

Functional C5 complement

C5 activity is measured by mixing patient serum with a C5-deficient serum. The lytic activity of the serum mixture is tested against sensitized, labeled liposomes. If lysis occurs, the patient serum must be the source of the C5. The target liposomes are a commercial reagent.(Unpublished Mayo method)


C5 antigen

Anti-C5 reagent is added to patient serum and quantitated on a Siemens BN II analyzer by fixed-time kinetic nephelometry.(Unpublished Mayo method)