Ordering Guidance

This test should be performed prior to treatment initiation and in the absence of therapy with complement inhibitors, such as eculizumab or ravulizumab. Complement inhibitors will affect performance of these assays.

For evaluating patients with possible thrombotic microangiopathies (TMA), the recommended first-tier test is ADM13 / ADAMTS13 Activity and Inhibitor Profile, Plasma. This test should be a second-tier test for TMA.

For patients who have received eculizumab or need to monitor response to eculizumab therapy, the recommended test is ECMP / Eculizumab Monitoring Panel, Serum. Soluble membrane attack complex should not be used as a standalone assay to monitor eculizumab efficiency.

For patients who have received ravulizumab or need to monitor response to ravulizumab therapy, the recommended test is RAVMP / Ravulizumab Monitoring Panel, Serum. Soluble membrane attack complex (sMAC) should not be used as a standalone assay to monitor ravulizumab efficiency.

Specimen Required

Both serum and plasma are required for this test.

Patient Preparation:

1. Fasting preferred but not required.

2. Do not collect specimens for at least 48 hours following plasma exchange.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Specimen Type: Serum

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL total in 3 separate plastic vials, each containing 0.5 mL

Collection Instructions:

1. Immediately after specimen collection, place the tube on wet ice and allow specimen to clot.

2. Centrifuge at 4° C and aliquot serum into 3 separate plastic vials, each containing 0.5 mL.

3. Within 30 minutes of centrifugation, freeze specimen. Sample 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.

Specimen Type: Plasma

Collection Container/Tube:

Preferred: Lavender top (K2 EDTA)

Acceptable: Lavender top (K3 EDTA), light-blue top (sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL total in 2 separate plastic vials, each containing 0.75 mL

Collection Instructions:

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

2. Centrifuge between 1000 and 2000 x g for 10 minutes at 4° C and aliquot plasma into 2 separate plastic vials, each containing 0.75 mL.

3. Within 30 minutes of centrifugation, freeze specimen. Sample 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 plasma is aliquoted and frozen.