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Test Code PTT Activated Partial Thromboplastin Time (PTT)

Performing Laboratory

Hunterdon Medical Center Laboratory

Useful For

The PTT (Activated Partial Thromboplastin) is used for the evaluation of the intrinsic coagulation pathway and the monitoring of heparin therapy.

The PTT is a good procedure to screen for deficiencies in the intrinsic coagulation pathway. Prolonged clotting times may be observed in deficiencies of Factors: XII, XI, X, IX, VIII, V, II or fibrinogen. Liver disease, Vitamin K deficiency, lupus anticoagulant or other inhibitors may also prolong the PTT.

Special Instructions

Note: Specimen must be filled to ETCHED line located on the Blue top tube to acheive a ratio of 9 parts blood to 1 part anticoagulant.

Specimen Required

Container/Tube: Blue Top (Na Citrate)

Specimen Volume: Must be filled to Etched line located on tube

Specimen Type

Citrated Plasma

Specimen Transport Temperature

Ambient temperature.

Specimen Stability

.

Patient status Temperature Time Frame
Heparinized Ambient 15-25°C 4 hrs uncentrifuged
Non-heparinized Ambient 15-25°C 24 hrs uncentrifuged

Reject Specimen Due To

Tube not properly filled, underfilled or overfilled.

Clotted

Hemolysis

Day(s) Test Set up

Monday through Sunday

Available STAT

Reference Values

Normal range: 25.1 - 36.5 secs

 

Therapeutic Range:  

The therapeutic range for Heparin Therapy is 0.2-0.4 U/ml.

This level of Heparin in the plasma results in an APTT range of 54.0-91.6 seconds.

1.5-2.5 times the normal PTT effectively heparinizes a patient, in most cases. 

The recommended therapeutic range for cardiology patients may be higher.

Methodology

Turbidimetric

CPT Code

85730

Loinc Code

14979-9