Test Code HIT 
Methodology Enzyme-linked Immunosorbent Assay (ELISA) 
Description Useful for heparin-induced platelet antibodies directed against heparin-PF4 complexes. 
Specimen 1. Draw blood in a light blue-top (3.2% sodium citrate) tube. Separate plasma from cells within 1 hour of collection and centrifuge at 2500 rpm for 15 minutes or 3000 rpm for 10 minutes.
NOTE: Specimen collected needs to be exactly 9 parts blood to 1 part 3.2% sodium citrate.
2. Using a plastic transfer pipette (do not use a glass pipette), decant the plasma to a screw-capped, plastic vial (do not aliquot to glass vial. Glass vials will not be accepted.)
3. Obtain a platelet count on the platelet-poor plasma. If the platelet count is > 10,000, respin the specimen and repeat steps 2 and 3 until the platelet count is < 10,000.
4. When the platelet count is acceptable, divide the specimen into as many 1.0 - 2.0 mL aliquots as possible and cap the vials tightly. Send at least 1.0 mL plasma.
5. FREEZE specimens immediately at or below -40C.
6. Send specimens FROZEN on dry ice. 
Reference Values Negative for HIT (type 2)

Critical value: Positive 

Analytic Time 1 Day testing - 2-3 days for report 
Day(s) Test Set Up Monday, Wednesday, Friday 
CPT Code(s) 86022