Coagulation Screening

Sample for Coagulation Screening tests

1. If plasma is needed, take 5 ml of venous blood and add sodium citrate as the anticoagulant.
2. Perform the assay immediately or as soon as possible.
3. For factors II, V, VII, and X,  place the citrated plasma on ice immediately, and the sample is stable for 2 hours.
   1. Freeze if it is delayed >2 hours.

Indications for coagulation screening tests:

1. Coagulation screening is done to find the cause of excessive bleeding.
2. Investigation of the possible cause of the bleeding disorder.

Definition of bleeding disorders:

1. Before we start workup of bleeding disorders, we should understand two systems of bleeding.
2. Bleeding disorders may be of two types:
   1. Primary hemostasis, related to:
      1. Platelets.
      2. Vascular defects.
   2. Secondary hemostasis related to:
      1. Coagulation factors defects.

Table to differentiate hemostasis:

The Coagulation Screening tests (profile) consist of the following:

1. Platelets.
2. Bleeding time.
3. Clotting time.
4. APTT.
5. PTT.
6. PT.
7. Clotting factor assay.

Platelet abnormality is seen in the following:

1. Idiopathic thrombocytopenia.
2. Low due to drugs.
3. Hypersplenism.
4. SLE.
   • (See more in Platelets)

Abnormal PTT alone is seen in:

• Bleeding due to a defect in factors VIII, IX, and XI  (8, 9, 11).

Abnormal PT alone is seen in:

• Bleeding due to a defect in Factor VIII (8).

Abnormal PTT + PT is seen in:

1. Anticoagulant therapy.
2. DIC.
3. Vit. K deficiency.
4. Liver diseases.
5. Rarely dysfibrinogenemia.
6. Rarely due to factor X, V, and II defects.

Interpretations of the blood coagulation screening profiles: