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, 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 specimen has clotted on wet ice, 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.