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Performing Laboratory

NorDx Laboratories

Useful For

Measuring heparin concentration in plasma

Method Name

Automated Colorimetric

Reference Values

Therapeutic range:

Twice daily dosing: 0.5-1.0 IU/mL (drawn 4 hours after dosing).

Once daily dosing: weak evidence suggests a therapeutic range of 1.0-1.5

IU/mL (drawn 4 hours after dosing).

Days and Times Test Performed

Monday through Friday, 8:00 am-3:00 pm

Specimens received outside this time frame will be processed the following day.

Analytic Time

1 Day

Specimen Type


Preferred Container

Light Blue Top Tube (Sodium Citrate) – Tube must be full at time of collection.

Preferred Volume

Plasma: 1 (Light Blue Top Tube (Sodium Citrate)) – aliquots

Minimum Volume

Plasma: 0.5 (Light Blue Top Tube (Sodium Citrate))

Specimen Collection and Handling

1. Separate plasma from cells within 1 hour of collection in a centrifuge at 2,500 rpm for 15 minutes or 3,000 rpm for 10 minutes.

2. Using a plastic transfer pipette (do not use a glass pipette) decant the plasma to a screw-capped, plastic (polypropylene) vial.

3. Spin the specimen again at the speeds mentioned above.

4. Using a plastic transfer pipette (do not use a glass pipette), divide the specimen into as many 0.5-1.0 mL aliquots as possible and cap the vial(s) tightly. Glass vials will not be accepted.

5. Freeze specimen(s) immediately at ≤ – 40º C.

6. Send specimen(s) FROZEN on dry ice.

Click here to view the Procedure for Collecting a Specimen from an A-line

NOTE: TYPE OF HEPARIN USED IS REQUIRED ON REQUEST FORM FOR PROCESSING (i.e., unfractionated, Lovenox, Fragmin, or Tinzaparin)

Rejection Information

Underfilled (<90 %), clotted, high hematocrit (>55 %), or grossly hemolyzed specimen

Specimen Stability Information

Specimen Type: Plasma

Frozen: 1 Month

Refrigerated: 1 Hour

Must be spun/separated within: 1 Hour

Add On Capable

Not Permitted

Advance Beneficiary Notice Requirements

No ABN Required

CPT Code Information

CPT Code

CPT Description

CPT Disclaimer

85520 Heparin Assay

Performing Laboratory Location

NorDx Laboratories