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Test Code APTT Partial Thromboplastin Time (APTT), Blood

Additional Codes

Epic Code

LAB325

Performing Laboratory

Bronson Laboratory Services-Coagulation

Reference Values

BMH

BBC                            

25-37 seconds

24 – 37 seconds

Therapeutic range

Patients on unfractionated heparin for treatment of
DVT/PE: 60-95 seconds

Patients on unfractionated heparin for cardiac/neurologic
protocols: 55-75 seconds

                                                         

Critical value (automatic call-back): ≥105 seconds

Critical value : ≥100 seconds

 

Methodology

Used for monitoring standard heparin therapy.

Specimen Requirements

Contact the laboratory if the patient’s hematocrit is over
55%, as a special tube must be provided for the blood draw.

Specimen
Type:
Whole blood

Container/Tube: Blue
top (3.2% sodium citrate)  

 

 

Specimen
Volume:
 
Full tube (2.7 mL or 1.8 mL)

Click here  to view the specimen collection guide for blue top (citrate) tubes.

 

 

Collection
Instructions:

 

  1. Tube must be filled to proper level as indicated by opaque line
    etched on each blue-top tube. Volume of blood is 2.7 mL
    in full draw (solid, light blue top) or 1.8 mL for partial draw
    (clear and blue top). The correct fill volume is indicated on the
    tube. Do not underfill.
  2. Gently invert 5 to 10 times to mix blood.
  3. If collected through a blood collection set (butterfly), a
    discard tube must first be drawn to eliminate dead space from
    tubing. 
  4. Causes for rejection include tube under filled tube,
    clotted specimen. or not processed within 4 hours of collection.

Laboratory Processing Instructions:

1. Spin down, remove plasma, and spin plasma
again
to obtain platelet poor plasma.

2. Separate platelet poor plasma into separate screw top
vials.

3. Freeze plasma immediately.

Specimen Transport Temperature

Ambient

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

85730