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HelpTest Code 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
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, SSpecimen Type
SerumSerum 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
Interpretation
Target trough therapeutic concentrations (immediately before next infusion) of ravulizumab are expected to be above 175 mcg/mL for paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. Pharmacodynamic studies of complement blockage may also be recommended for patients undergoing therapy.
For the complement blockage monitoring of ravulizumab:
-When ravulizumab is present in serum at concentrations around 50 mcg/mL, the results range from 20% to 29% of normal.
-When ravulizumab concentrations are around 100 mcg/mL, the results range from below 10% to 13% of normal.
-When ravulizumab concentrations are greater than 200 mcg/mL, the results are below the limit of quantitation of the assay (<10% of normal).
Clinical Reference
1. Willrich MAV, Ladwig PM, Martinez MA, et al. Monitoring ravulizumab effect on complement assays. J Immunol Methods. 2021;490:112944. doi:10.1016/j.jim.2020.112944
2. Go RS, Winters JL, Leung N, et al. Thrombotic microangiopathy care pathway: A consensus statement for the Mayo Clinic Complement Alternative Pathway-Thrombotic Microangiopathy (CAP-TMA) Disease-Oriented Group. Mayo Clin Proc. 2016;91(9):1189-1211 doi:10.1016/j.mayocp.2016.05.015
3. Ardissino G, Tel F, Sgarbanti M, et al. Complement functional tests for monitoring eculizumab treatment in patients with atypical hemolytic uremic syndrome: an update. Pediatr Nephrol. 2018;33(3):457-461
4. Volokhina EB, van de Kar NC, Bergseth G, et al. Sensitive, reliable and easy-performed laboratory monitoring of eculizumab therapy in atypical hemolytic uremic syndrome. Clin Immunol. 2015;160(2):237-243
5. Cataland S, Ariceta G, Chen P, et al. Discordance between free C5 and CH50 complement assays in measuring complement C5 inhibition in patients with aHUS treated with ravulizumab. Blood. 2019;134(Supplement_1):1099
6. Ladwig PM, Barnidge DR, Willrich MA. Quantification of the IgG2/4 kappa monoclonal therapeutic eculizumab from serum using isotype specific affinity purification and microflow LC-ESI-Q-TOF Mass Spectrometry. J Am Soc Mass Spectrom. 2017;28(5):811-817. doi: 10.1007/s13361-016-1566-y
7. Kulasekararaj AG, Hill A, Rottinghaus ST, et al. Ravulizumab (ALXN1210) vs eculizumab in C5-inhibitor-experienced adult patients with PNH: the 302 study. Blood. 2019;133(6):540-549. doi:10.1182/blood-2018-09-876805
8. Stern RM, Connell NT: Ravulizumab. a novel C5 inhibitor for the treatment of paroxysmal nocturnal hemoglobinuria. Ther Adv Hematol. 2019;10:2040620719874728. doi:10.1177/2040620719874728
9. Alexion Pharmaceuticals. BLA 761108-S1 Multi-disciplinary review and evaluation: Ultomiris (ravulizumab-cwvz). FDA; April 2, 2019. Accessed August 7, 2023. Available at www.fda.gov/media/135113/download
10. Vu, T, Meisel, A, Mantegazza, R, et al. Terminal complement inhibitor ravulizumab in generalized myasthenia gravis. N Engl J Med Evid. 2022;1(5):1-12. doi:10.1056/EVIDoa2100066
11. Sridharan M, Go RS, Willrich MAV. Clinical utility and potential cost savings of pharmacologic monitoring of eculizumab for complement-mediated thrombotic microangiopathy. Mayo Clin Proc Innov Qual Outcomes. 2022;6(5):458-464. doi:10.1016/j.mayocpiqo.2022.03.005
Day(s) Performed
Varies
Report Available
3 to 10 daysPerforming 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 |