Ordering Guidance

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

Specimen Required

Patient Preparation:

1. Fasting: 8 hours, preferred but not required

2. Suggest discontinuing natalizumab at least 4 weeks before specimen collection for ravulizumab testing. Patient should consult the healthcare professional who prescribed this drug to determine if discontinuation is an option. If not, it is okay 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 Serum 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 and allow specimen to clot.

3. Centrifuge at 4° C and aliquot serum into two 5 mL plastic vials.

4. Freeze serum within 30 minutes of centrifugation. Serum 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 sample is kept on ice before centrifugation, and immediately afterward, the serum is aliquoted and frozen.