Skip Ribbon Commands
Skip to main content
Sign In
Navigate Up

22702 Heparin, Unfractionated

Heparin, Unfractionated
Test Code: HEPUF
Synonyms/Keywords
Heparin-unfract, Unfractionated Heparin​, Xa, Anti-Xa
Useful For
Monitoring unfractionated heparin therapy.
If monitoring low molecular weight heparin (Lovenox, etc), then order Heparin, Low Molecular Weight (HEPLMW).
If monitoring fondaparinux (Arixtra), then order Fondaparinux (ARIXTRA).​
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
*Platelet Poor Plasma 3.2% ​Citrated Blue Top Tube (BTT) ​ 0.75 mL​ 0.75 mL​ 0.5 mL ​
Collection Processing Instructions
One 0.75 mL citrated Blue Top Tube (BTT) plasma aliquot.
If more than one coagulation test is ordered, a separate aliquot is needed for each test.
-Collect in Citrated Blue Top Tube (BTT)
-Citrate anticoagulant must be adjusted for HCT >55%
-Tube must be at least 90% full
-Invert completely 3-4 times (without shaking) to mix
*See Instructions for: Preparation of Platelet Poor Plasma ​
Specimen Stability Information
Specimen Type Temperature Time
​Plasma (stored on cells or platelet poor aliquot) Room Temperature (15 to 25 degrees C) 4 hours
​Platelet Poor Plasma​Frozen (< or = -18 degrees C)​3 days
​Platelet Poor Plasma​Frozen (< or = -74 degrees C)​3 months
Rejection Criteria
​Specimen tubes under-filled (below the fill line) and over-filled (above the fill line)
​Gross Hemolysis
​Clotted
Frozen whole blood
​Contamination with IV or Hickman Line fluids
​Specimens that thaw during storage or transport
​Specimens with HCT >55% that have not had the citrate anticoagulant adjusted
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Marshfield ​Monday through Friday
8 am - 4 pm
 ​Less than 2 hours ​Anti-Factor-Xa Chromogenic/Siemens Sysmex CS 2500
Reference Range Information
Performing Location Reference Range
​Marshfield

When measured by the anti-Xa method, the recommended therapeutic range for unfractionated heparin is 0.30-0.70 IU/mL. (Chest 2008; 133(6S):141S-159S)

See Critical Value Policy for list of current critical values

Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​85520 ​ ​ ​
Synonyms/Keywords
Heparin-unfract, Unfractionated Heparin​, Xa, Anti-Xa
Ordering Applications
Ordering Application Description
​Cerner Heparin, Unfractionated​

If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
*Platelet Poor Plasma 3.2% ​Citrated Blue Top Tube (BTT) ​ 0.75 mL​ 0.75 mL​ 0.5 mL ​
Collection Processing
One 0.75 mL citrated Blue Top Tube (BTT) plasma aliquot.
If more than one coagulation test is ordered, a separate aliquot is needed for each test.
-Collect in Citrated Blue Top Tube (BTT)
-Citrate anticoagulant must be adjusted for HCT >55%
-Tube must be at least 90% full
-Invert completely 3-4 times (without shaking) to mix
*See Instructions for: Preparation of Platelet Poor Plasma ​
Specimen Stability Information
Specimen Type Temperature Time
​Plasma (stored on cells or platelet poor aliquot) Room Temperature (15 to 25 degrees C) 4 hours
​Platelet Poor Plasma​Frozen (< or = -18 degrees C)​3 days
​Platelet Poor Plasma​Frozen (< or = -74 degrees C)​3 months
Rejection Criteria
​Specimen tubes under-filled (below the fill line) and over-filled (above the fill line)
​Gross Hemolysis
​Clotted
Frozen whole blood
​Contamination with IV or Hickman Line fluids
​Specimens that thaw during storage or transport
​Specimens with HCT >55% that have not had the citrate anticoagulant adjusted
Useful For
Monitoring unfractionated heparin therapy.
If monitoring low molecular weight heparin (Lovenox, etc), then order Heparin, Low Molecular Weight (HEPLMW).
If monitoring fondaparinux (Arixtra), then order Fondaparinux (ARIXTRA).​
Reference Range Information
Performing Location Reference Range
​Marshfield

When measured by the anti-Xa method, the recommended therapeutic range for unfractionated heparin is 0.30-0.70 IU/mL. (Chest 2008; 133(6S):141S-159S)

See Critical Value Policy for list of current critical values

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Marshfield ​Monday through Friday
8 am - 4 pm
 ​Less than 2 hours ​Anti-Factor-Xa Chromogenic/Siemens Sysmex CS 2500
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​85520 ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.