Sign in →

Test Code LMWH Low Molecular Weight Heparin Anti-Xa Assay

Important Note

Specimen must be taken 4 hrs post injection of low molecular weight heparin.

Specimen collection time for peak or trough level should be indicated.

Additional Codes

Epic Ordering Code LAB2207
NBS code LBC2686
Service code 12434

Specimen Requirements

Submit the following: 

 

Preferred:
Light Blue Top

Processing Requirements

Submit only one of the following specimens


Specimen Type: Whole Blood
Container/Tube: 2 Light Blue Top (3.2% Sodium Citrate)
Volume: 2 × 2.7 mL Whole Blood (Tubes must be full)
Collection Instructions: Send whole blood specimens to laboratory immediately.


Specimen Type: Platelet Poor Plasma
Container/Tube: 2 Light Blue Top (3.2% Sodium Citrate)
Submission Container/Tube: Plastic Vial

Minimum Volume: 1.0 mL plasma
Collection Instructions:
1. Light blue top tube must be properly filled with whole blood.

2. Whole blood specimen should be double centrifuged and plasma separated from cells within 1 hr of collection.
3. Plasma should be separated into 2 aliquots with minimum volume of 1.0 mL each.
4. Freeze the aliquots in well-closed plastic tubes immediately.

Specimen Stability

Specimen Type Plasma
Ambient 4 hours
Refrigerate 4 hours
Frozen 14 days (preferred)

Specimen Condition

Haemolysis Gross reject
Icterus Gross reject
Lipaemia Gross reject
Others Clotted or insufficient reject

Methodology

Chromogenic Assay

Days and Times Performed

Monday through Friday, TAT 7 days

Reference Interval

Enoxaparin, Nadroparin (1mg/kg/12hr) 0.60 – 1.00 IU/mL
Tinzaparin (175 Anti-Xa IU/kg/24hr) > 0.85 IU/mL

Testing Laboratory

National University Hospital
Haematology, 67725320

Useful For

Monitoring of low molecular weight heparin therapy.

Update

Last updated 22/06/2026

Alias

LMWH
Anti-Xa