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American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Platelet Mapping, ADP with Thromboelastograph

Test Code(s): ADPTEG / HCADPTEG

CPT Code(s): 85576

Test Description: Test Component:

Platelet Mapping ADP, TEG-Patient not on Heparin test must be ordered at the same time of Platelet MappingTest.  Maximum Amplitude, Angle, Clot Strength and Clot Time will be performed. Indicate whether baseline or Drug Therapy in Comment Section of Healthlink order. 


Methodology: Thromboelastography

Clinical Significance: Assessment of platelet inhibiton by clopidogrel(Plavix®)

Days Performed: Mon-Fri, 0800-1500 - day varies. Specimens will not be accepted prior to 0800 or after 1500. Testing required during off hours must be approved by a Coagulation physician. Call 263-5005 before collection.

Turnaround Time: Stat: 2 hours.
Routine: 2 hours.


Specimen Requirements

Specimen: Blood

Collection Instructions: Note if patient is on clopidogrel (Plavix®) and the dosage. DO NOT draw through a line containing heparin. The venipuncture MUST be atraumatic to avoid hemolysis, contamination with tissue factors, or platelet activation. Tubes must allowed to fill completely.  

Collection Container: Preferred: Green top (Na Heparin) and light blue top (3.2% NaCitrate)

Collection Volume: Preferred: 1-4 mL green top and 1-3.5 mL lt. blue top
Pediatrics: 1-4ml green top and 1-1.8 ml lt. blue top

Sample Analyzed: Whole Blood

Volume Required: Preferred: 1-4 mL green top and 1-3.5 mL lt. blue top
Pediatrics: 1-4ml green top and 1-1.8 ml lt. blue top

Specimen Processing: Do NOT freeze, refrigerate, or centrifuge.  Do NOT open tube. Do NOT send through pneumatic tube.

Specimen Transport: Hand deliver specimen to UWHC Core Laboratory( B4/220)  ASAP.  Do NOT send through pneumatic tube.  

Unacceptable Criteria: Hemolyzed or clotted specimens are not acceptable.  A partially filled tube is NOT acceptable.  

Stability: Ambient: 2 hours unspun
Refrigerated: Not acceptable
Frozen: Not acceptable


Interpretation

Result will be reported in % inhibition.  Since there is limited data available to assist in interpretation of these results, correlation of the test result with clinical information is strongly advised. The response to clopidogrel as measured by this test is more variable than the response to aspirin.  In one study of individuals taking 75 mg/day of clopidogrel, 40% of patients had less than 30% inhibition of ADP-induced aggregation, 25% had between 30 and 50% inhibition, and 35% had more than 50% inhibition.  Reference: Agarwal et al. Quantifying the effect of antiplatelet therapy.  Anesthesiology 2006;105:676-83.

Platelet Mapping clopidogrel(Plavix®),Platelet Inhibition by clopidogrel(Plavix®,PMADP

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