Jul 20, 2017




Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Coagulation

ADAMTS13 Activity, Reflex to Inhibitor

ADAMTS13 Activity, Reflex to Inhibitor (ADAMACT) Coagulation Lab Test

Name: ADAMTS13 Activity, Reflex to Inhibitor

Test Name: ADAMTS13 Activity, Reflex to Inhibitor

Health Link Test Code: ADAMACT

LIS Test Code: ADAMTS13

CPT Code(s): 85397

Methodology: ELISA

Clinical Information:

Test is used to assist in diagnosing congenital or inherited thrombotic thrombocytopenic purpura (TTP).

Days Performed: Daily- Specimens are accepted at any time. Testing required during off hours must be approved by a Coagulation physician. Call (608)263-5005 before collection.

In-Lab Turnaround Time: 2 days.

Stat In-Lab Turnaround Time: 1 day.

Specimen: Blood

Collection Container: Light blue top (3.2% NaCitrate)

Collection Volume: Full 3.5 mL tube

Pediatric Collection Volume: Pediatric tube filled to fill mark

Stability Ambient:

2 hours unspun

Stability Refridgerated:

Not acceptable

Stability Frozen:

2 months at -20

Testing Volume: 0.5 mL

Pediatric Testing Volume: 0.3 mL

Specimen Processing:

Centrifuge specimen to yield platelet poor plasma (platelet count should be less than 10K/µL). Separate plasma and transfer to a plastic tube or vial. Freeze plasma at -200C.

Specimen Transport:

Transport whole blood specimen at room temperature to UWHC Hospital Laboratory to be received within 2 hours of collection. If unable to transport the specimen to reach the UWHC lab within 2 hours see Specimen Processing for instructions. Transport frozen aliquot on dry ice to UWHC Hospital Laboratory.

Unacceptable Criteria:

Hemolyzed specimens, clotted specimens, partially filled tubes and whole blood specimens greater then 2 hours old when received by the laboratory are not acceptable.


Results > 60% are considered normal. Results < 10% ADAMTS13 are highly indicative of thrombotic thrombocytopenia purpura (TTP) in an appropriate clinical setting. 

If the ADAMTS13 Activity is < 10% an ADAMTS13 inhibitor order will reflex and the sample will be sent to a reference laboratory for inhibitor testing.


The performance charateristics of this test were validated by the UWHC Clinical Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test, however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management.