Sign in →

Test Code LAB5333 Heparin Anti-Xa - (ACL TOP 500)

Important Note

The heparin anti-Xa test is not routinely ordered, but may be performed whenever a doctor wants to evaluate UFH or LMWH concentrations in the blood. It may be ordered periodically to monitor UFH therapy, especially when a doctor feels that a person is not responding as expected to UFH or when the PTT is not useful.

When it is used as a LMWH monitoring tool, heparin anti-Xa is primarily ordered as a "peak" test. It is collected 4 hours after an LMWH dose is given, when the concentration of LMWH in the blood is expected to be at its highest level. Random and "trough" anti-Xa tests may also be ordered when a doctor suspects that someone may not be clearing the

LMWH at a normal rate. Trough tests are collected just prior to the next dose, when heparin concentrations are expected to be at their lowest.

Performing Laboratory

Asante Rogue Regional Medical Center (ARRMC)

Specimen Minimum Volume

1 properly filled 4.5 mL blue top tube

Specimen Requirements

TRMC and AACH

Specimens are only good for 4 hours. Specimens that do not arrive at ARRMC Lab within 2 hours must separate and freeze the plasma.

 

Blue top tube 4.5 mL Sodium Citrate

 

Peak samples – draw at 4 hours after LMWH dose is given (but no later than 6 hours).

Trough samples – draw just prior to the next dose (about 15 minutes).

 

Also, acceptable:

Blue top tube 2.7 mL Sodium Citrate or Blue top tube 1.8 mL Sodium Citrate is an acceptable blue top tube.

 

RRMC      Heparin Anti-Xa Level Memo July 30, 2015

 

TRMC      Heparin Anti-Xa Level September 16, 2015

Specimen Transport Temperature and Stability

Mix and centrifuge immediately at 2500 RPM for 10 minutes.

Or Centrifuge specimen via the STAT-SPIN® for 3 minutes

Specimen is stable for 4 hours.

 

TRMC and AACH

Specimens that are not received at ARRMC lab within 2 hours, must separate and freeze the plasma.

Reasons for Rejection

Quantity not sufficient (QNS)

Specimens not filled to correct volume

Lacking Two Patient Identifiers:

         1-Patient's First & Last name 

         2-Patient's Date of Birth

Day(s) Test Set Up

Monday through Sunday

Routine - same day

ASAP - 2 hours after receipt of specimen in lab

STAT - 1 hour after receipt of specimen in lab

Additional Information

Limitations:

Heparin results on the ACL TOP® Family are not affected by:

  • Hemoglobin up to 300 mg/dL
  • Bilirubin up to 20 mg/dL
  • Triglycerides up to 800 mg/dL

Methodology

Chromogenic assay

Performing Department

Coagulation / Hematology

Test Classification and CPT Coding

85520 - Heparin assay