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Test Code LAB316 Low Molecular Weight (LMW) Heparin, Blood Level

Test Name Alias

Low Molecular Weight Heparin (Chromogenic substrate methodology) Blood Level |LMWH |Anti Xa Blood Level | Lovenox level | 8102

Collection Instructions

Specimen Collection: Blood

 

Container(s): 4.5 mL Blue top (3.2% Na. Citrate) or 1.8 mL Clear/Blue top (3.2% Na. Citrate)

Preferred Volume to Collect: 4.5 mL (Tube must be full)

Minimum Volume to Collect: 1.8 mL (Tube must be full)

Capillary collect ok: No

Microtainer acceptable: Yes, 1.8 mL clear/blue top must be full

 

Collection Instructions:

  • Sample should be collected 4 hours after subcutaneous injection.

  • Detailed instructions: Blue Citrate Tube

  • Obtain venous blood by clean venipuncture.

  • Avoid leaving the tourniquet on the patient’s arm for an extended period prior to collection.
  • Tube must be full. Do not over fill or under fill; look for the fill indicator lines.
  • Gently invert 8 – 10 times to mix anticoagulant with blood.
  • Specimen should be processed within 1 hour – See Processing Instructions.

Processing Instructions (Laboratory, Outpatient or Off-site collection)

Processed Specimen: Platelet Poor Plasma

Centrifuge/Spin: Yes

Aliquot: Yes

 

Processing Instructions:

  • Tube must be double spun within 1 hour of collection.
  • Spin down sodium citrate specimen collection tube, remove plasma from the specimen tube.
  • Place specimen in primary aliquot transport tube.
  • Centrifuge primary aliquot transport tube
  • Remove plasma from primary aliquot tube, carefully leaving a small portion containing cell byproducts at the bottom.
  • Place plasma from primary aliquot tube in secondary aliquot tube.
  • Submit secondary aliquot tube for testing

Platelet poor plasma specimens are critical for accurate result.   Platelet contamination may cause spurious results.  To obtain platelet poor plasma centrifuge specimen and remove plasma without disturbing cellular components.  Platelet count in plasma aliquot should be less than 10,000/μL.

 

Transport Temperature: Frozen

Special Instructions

Sample should be collected 4 hours after subcutaneous injection.

To obtain a coagulation plasma sample, centrifuge the capped specimen tube at a speed and time required to consistently produce platelet-poor plasma (platelet count <10,000/uL).The centrifugal speed and duration to accomplish this must be established by the individual laboratory. Our laboratory use centrifuges at 3800 rpm for ten minutes or higher speed and shorter duration centrifuges.  When removing plasma to send to the Coagulation department, it is important NOT to go all the way down to the cells. Leave a minimum ¼ inch of plasma sitting on cells. This layer contains the platelets which were separated from the plasma during spinning. Leave this layer undisturbed as platelets interfere with coagulation testing.

Specimen Stability

Ambient: 1 Hour

Frozen: 2 Months (Platelet poor plasma aliquot and freeze within 1 hour of collection)

Laboratory Retention: 2 Months

Test Frequency

Available Monday – Friday (dayshift), usual TAT 1 – 4 days.

Reference Range

The therapeutic range for anticoagulation with LMW heparin has been reported to be 0.5-1.0 U/ml and the prophylactic range as 0.2-0.4 U/ml when measured by the anti-Xa method, with samples drawn 3-4 hours after SQ administration of either dalteparin or enoxaparin.  

 

Laboratory Critical Values Table

Clinical Information

Plasma low molecular weight heparin (LMWH) anti-Xa assay assayed using a low molecular weight heparin reference curve. This assay is valid only for low molecular weight heparin, and will not accurately reflect anti-Xa activity in patients on unfractionated heparin or danaparoid.

Performing Department

Coagulation

Performing Department Laboratory Location

Spectrum Health Regional Laboratory (SHRL), Grand Rapids, MI

Methodology

Chromogenic Based Assay

CPT

85520

CDM Code

4094121

Interface Order Alias

10199

Mayo Access Code

SHO8102

Reviewed Date

7/1/2017