Activated Partial Thromboplastin Time

Test Code

PTT

Alias/See Also

APTT, PTT, Activated Partial Thromboplastin,

CPT Codes
85730

Preferred Specimen

Citrate BLUE (BLU)

Instructions

Collect whole blood in 3.2% buffered sodium citrate (9:1 blood to sodium citrate). Venipuncture must be atraumatic.

Specimen Stability

Refrigerated/Ambient Temperature: Specimens for PTT assays uncentrifuged or centrifuged, when kept at 2 to 4°C or 18 to 24°C, should be tested within 4 hours from the time of specimen collection.
Frozen Plasma: If testing is to be delayed more than 24 hours after collection, immediately separate plasma into a clean, polystyrene tube, cap, and store below –20°C up to two weeks or -70°C up to 6 months.

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Reject hemolyzed, clotted, overfilled tubes or short draw (<90%) samples.

Methodology
Diagnostic Stago

Setup Schedule

24x7

Limitations

Result Range: 15-120 Seconds

Reference Range

Referenc Range:: 23.0-36.5 seconds
Critical >100 seconds

Recommended therapeutic range for heparinization: 65-95 seconds

High intensity unfractionated heparin (patients > 13 years): Target aPTT is 65 to 90 sec
High intensity unfractionated heparin (patients <13 years): Target aPTT is 60 to 85 sec
Low intensity unfractionated heparin: Target aPTT is 50 to 70 sec
Ultra low intensity unfractionated heparin: Target aPTT is 41 to 50 sec

Clinical Significance

The activated partial thromboplastin time (APTT) is a screening test for deficiencies of all coagulation factors except factors VII, XIII, and platelets. Citrated plasma provides all factors of the intrinsic coagulation pathway except calcium and platelet factors. In the test system an excess of platelet-like reagent is added, calcium is restored, and the clotting time is noted.

Performing Laboratory
CRMC Laboratory
CCMC Laboratroy
FHSH Laboratory

The CPT Codes provided in this document 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 payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.