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Test ID RAVMP Ravulizumab Monitoring Panel, Serum


Ordering Guidance


To measure only serum concentration of ravulizumab, order RAVU / Ravulizumab, Serum.



Specimen Required


Patient Preparation:

1. Fasting preferred.

2. Suggest discontinuing natalizumab at least 4 weeks prior to testing for ravulizumab quantitation in serum. Patient should consult the healthcare provider who prescribed this drug to determine if discontinuation is an option. If not, ok to proceed with testing while taking natalizumab.

Supplies: Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Red top (serum gel/SST are not acceptable)

Submission Container/Tube: 2 Plastic vials

Specimen Volume: 2 mL in 2 plastic vials, each vial containing 1 mL

Collection Instructions:

1. Draw blood immediately before next scheduled dose.

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

3. After sample has clotted on wet ice, centrifuge at 4° C and aliquot serum into two 5 mL plastic vials.

4. Freeze specimen within 30 minutes of centrifugation. Sample must be placed on dry ice if not frozen immediately.


Useful For

Monitoring of complement blockage by ravulizumab

 

Assessing the response to ravulizumab therapy

 

Assessing the need for dose escalation

 

Evaluating the potential for dose deescalation or discontinuation of therapy in remission states

 

Monitoring patients who need to be above a certain ravulizumab concentration in order to improve the odds of a clinical response for therapy optimization

Highlights

Ravulizumab is a therapeutic monoclonal antibody targeting complement C5 with a longer half-life than eculizumab. Monitoring the complete complement blockade by eculizumab has allowed personalized therapy in specific settings. Similar action is expected with ravulizumab. Ravulizumab has 4 different amino acids from eculizumab, which allow greater affinity for the FcRn immunoglobulin receptor and change the affinity of the molecule for C5.

 

Therapeutic drug monitoring of ravulizumab may be useful when patients need to be above a certain target or therapeutic threshold of the monoclonal antibody concentration to improve odds of a clinical response for therapy optimization or potential dose deescalation or discontinuation of therapy in remission states.

Profile Information

Test ID Reporting Name Available Separately Always Performed
RAVU Ravulizumab, S Yes Yes
RAVUM Ravulizumab Complement Blockage, S No Yes
RAVIN Ravulizumab Interpretation, S No Yes

Method Name

RAVUM: Enzyme-Linked Immunosorbent Assay (ELISA)

RAVU: Liquid Chromatography Tandem Mass Spectrometry, High Resolution Accurate Mass (LC-MS/MS HRAM)

Reporting Name

Ravulizumab Monitoring Panel, S

Specimen Type

Serum
Serum Red

Specimen Minimum Volume

1 mL in 2 plastic vials, each vial containing 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen 14 days
Serum Red Frozen 14 days

Reference Values

RAVULIZUMAB COMPLEMENT BLOCKAGE:

≥46% normal

 

RAVULIZUMAB:

Lower limit of quantitation =5.0 mcg/mL

>175 mcg/mL: Therapeutic concentration for paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome

Day(s) Performed

Varies

Report Available

3 to 10 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. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80299

86161

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RAVMP Ravulizumab Monitoring Panel, S 101923-1

 

Result ID Test Result Name Result LOINC Value
609500 Ravulizumab Complement Blockage, S 74520-8
609420 Ravulizumab, S 97184-6
619952 Ravulizumab Interpretation 59462-2

NY State Approved

Yes