Activated Partial Thromboplastin Time (APTT/PTT)

Cleveland HeartLab A, Test

CPT Code: 85730
Order Code: C2441
ABN Requirement: No
Synonym: APTT; Partial Thromboplastin Time; PTT
Specimen: Sodium Citrate Plasma
Volume:  1.0 mL
Minimum Volume:  0.5 mL
Container: Sodium citrate (Light Blue top) tube


Sodium Citrate Plasma:

  1. Draw a full tube and gently invert 3 to 4 times.
  2. Centrifuge for 10 minutes.
  3. Pre-squeeze transfer pipet bulb and draw off approximately 2/3 of the upper plasma layer.
    Note: This ensures that the buffy coat and red cells remain undisturbed.
  4. Aliquot plasma into labeled transport tube and cap tightly. Discard original tube.
  5. Store transport tube refrigerated at -20°C until ready to ship.

Transport: Store plasma at -20°C after collection and ship the same day per packaging instructions provided with the Cleveland HeartLab shipping box.

  • Please note: Ship frozen sodium citrate plasma on dry ice.

Special Information: Sodium citrate collection tube must be filled to total fill volume.


Ambient (15-25°C): 4 hours
Refrigerated (2-8°C):
Frozen (-20°C):
14 days
Deep Frozen (-70°C):
6 months

Causes for Rejection: Specimens other than sodium citrate plasma; improper labeling; samples not stored properly; samples older than stability limits; sample received not frozen

Methodology: Automated Optimal Clot Detection

Turn Around Time: 2-3 days

Reference Range:

Age sec
0-1 days 27.1-43.7
2-5 days 22.0-48.0
6-30 days 22.1-44.3
1-3 months 20.8-40.2
4-11 months 24.3-34.4
1-99 years 23.0-32.4


Urgent Range:

Age sec
All Ages >100.0


Intended Use: Evaluation of hemostasis.

Clinical Significance: APTT/PTT may be used to investigate unexplained bleeding or clotting. Proteins called coagulation factors are involved in hemostasis and the formation of blood clots. The combination of APTT/PTT with Prothrombin Time (PT/INR) may give additional insight into a bleeding or clotting disorder.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.