UNIVERSITY OF SANTO TOMASFACULTY OF PHARMACY

DEPARTMENT OF MEDICAL TECHNOLOGYPrinciples and Strategies of Teaching in Health Education

TEACHING DEMONSTRATION

ACTIVATED PARTIAL THROMBOPLASTIN TIME

I. OVERVIEW

This test is also known as partial thromboplastin time with Kaolin (PTTK), and the Kaolin

Cephalin Clotting Time (KCCT).

II. PRINCIPLE

The test measures the clotting time of plasma after the activation of contact factors but

without added in tissue extract (thromboplastin) and so indicates the overall efficiency of the

intrinsic clotting system. To standardize the activation of the contact factors, the plasma is first

pre-incubated with Kaolin. A standardized phospholipid is provided to allow the test to be

performed in platelet poor plasma. The test not only depends on the contact factors and VIII and

IX, but also on the reactions with factors X, V, Prothrombin and Fibrinogen. It is also sensitive to

the presence of circulating anticoagulants (inhibitors) and heparin.

III. REAGENTS

A. Patient and control citrated plasma (PPP).

B. APTT reagent, (phospholipid + Kaolin)

C. CaCl2 0.025 mol/l.

IV. METHOD

A. Keep the reagent in 37 OC for 10 min

B. Add 0.1 ml of PTT reagent.

C. Add 0.1 ml of plasma and incubate the mixture for 3 min at 37 OC

D. Add 0.1 ml of pre-warmed CaCl2 and mix the contents of the tube.

E. Start the stop-watch and record the end point.

F. Carry out the test in duplicate on the patient's and control plasma.

UNIVERSITY OF SANTO TOMASFACULTY OF PHARMACY

DEPARTMENT OF MEDICAL TECHNOLOGYPrinciples and Strategies of Teaching in Health Education

TEACHING DEMONSTRATION

V. NORMAL RANGE

The normal range for this test is 30-40 seconds.

VI. INTERPRETATION:

The common causes of prolonged PTTK in acute hemostatic failure are:

A. The administration of heparin or contaminated with heparin.

B. Liver diseases.

C. Disseminated Intravascular Coagulation.

D. Coagulation factor deficiency or deficiency, hemophilia A, hemophilia B, and

factor IX and factor XII, PK, HMWK, V, Prothrombin or fibrinogen deficiency.

E. Massive transfusion with stored blood.