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Test Code 1UFH Heparin, Unfractionated

Additional Codes

EPIC LAB4257

Synonyms

  • Anti-Xa
  • Fragmin (Dalteparin)
  • Lovenox (Enoxaparin)

Clinical Significance

Heparin is the most frequently used antithrombotic drug. The biological activity of the sulphated glycosaminoglycan resides in its ability to accelerate (up to 2000-fold) the inhibitory effect of antithrombin on coagulation proteases.

 

Source: HemosIL Liquid Anti-Xa PN 0020302600 IFU

Methodology

Heparin is analyzed as a complex with antithrombin present in the sample. The concentration of this complex is dependent on the availability of the patient's endogenous antithrombin. When the heparin-antithrombin complex is formed, two competing reactions take place.

  1. Factor Xa is neutralized by the heparin-antithrombin complex.
  2. Residual Factor Xa is quantified with a synthetic chromogenic substrate. The paranitroaniline released is monitored kinetically at 405 nm and is inversely proportional to the heparin level in the sample.

In order to reduce the influence from heparin antagonists, such as platelet factor 4 (PF4), dextran sulfate is included in the reaction mixture.

Sample Type

Preferred Sample Type
Light blue top - Na Citrate Plasma

Centrifuge: Yes

Specimen Minimum Volume

0.5 mL

 

NOTE: Na Citrate Blue top tubes require that the tube is filled adequately to maintain the 9:1 blood to anticoagulant ratio.

Specimen Stability

Temperature Time
Ambient (18-25°C) (store) 2 hours
Refrigerated (2-8°C) N/A
Frozen (<-20°C) N/A

NOTE: Separate plasma from cells within 2 hours

Reference Ranges

Therapeutic Range
0.3 - 0.7 IU/mL

 

 

Critical Value
>0.80 IU/mL

 

Rejection Criteria

Hemolysis N/A
Icterus N/A
Lipemia N/A
  • Clotted samples
  • Underfilled or overfilled samples

Availability

Performed STAT
24/7 Yes

 

Performing Laboratory

MultiCare Yakima Memorial Hospital Laboratory

Lab Department

Hematology

CPT Code

85520

LOINC

3273-0 Heparin unfractionated Coag Qn (PPP)

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