Activated partial thromboplastin time

Activated Partial thromboplastin time (APTT) – role in the body

APTT is a key indicator that evaluates the internal pathway of blood clotting. -the time it takes for a blood clot to form after the addition of specific activators.

Physiological role:

1. Evaluation of plasma coagulation factors (VIII, IX, XI, XII)
2. Control of heparin therapy
3. Diagnosis of hemophilia
4. Detection of vitamin K deficiency (indirectly)
5. Assessment of liver function (synthesis of clotting factors)

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APTT norm in the blood test

Group	Normal Values
Adults	25–35 seconds
Newborns	25–43 seconds
On Heparin Therapy	45–70 seconds

Note: References may vary slightly in different laboratories.

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Symptoms of APTT lengthening (hypocoagulation)

Main reasons:

• Hemophilia A / B (factor VIII/IX deficiency)
• Willebrand’s disease
• Heparin therapy
• DIC-syndrome (hypocoagulation phase)
• Vitamin K deficiency
• Autoimmune antiphospholipid antibodies

Clinical manifestations:

1. Hemorrhagic syndrome:

• Hematomas with minimal injuries
• Hemarthrosis (hemorrhage in the joints)
• Prolonged bleeding after tooth extraction

1. Spontaneous bleeding:

• Nasal ones
• Gastrointestinal problems
• Uterine (menorrhagia)diseases

1. Postoperative complications:

• Bleeding stitches
• Formation of hematomas

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Symptoms of APTT shortening (hypercoagulation)

Main reasons:

• The initial stage of DIC-syndrome
• Thrombophilia
• Oncological diseases
• Pregnancy (physiological shortening)

Clinical manifestations:

1. Thrombotic complications:

• Deep vein thrombosis (edema, cyanosis of the limb)
• PE (shortness of breath, chest pain)

1. Ischemic lesions:

• Myocardial infarction
• Ischemic stroke

1. Obstetric complications:

• Habitual miscarriage
• Placental insufficiency

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Diagnostic algorithm for deviations

If the APTT is extended:

1. Exclude heparin therapy
2. Determine the activity of factors VIII, IX, XI
3. Investigate antiphospholipid antibodies
4. Evaluate liver function

If the APTT is shortened:

1. Exclude DIC-syndrome
2. Check your fibrinogenFibrinogen is a protein, one of the main blood clotting factors. It is necessary for the formation of blood clots and stopping bleeding, helps in healing damaged tissues and restoring their blood supply. When the wall of a vessel of any caliber is damaged, a cascade of biochemical reactions is triggered in the blood, the final stage of which is the conversion of fibrinogen into fibrin. A blood clot is formed. Fibrinogen is synthesized by liver cells and is constantly present in the blood at a certain concentration. level
3. Test for thrombophilia
4. Oncopoisk if necessary

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Correction of violations

With increased APTT with bleeding:

1. For hemophilia-administration of factor concentrates
2. For Willebrand’s disease-desmopressin
3. Overdose of heparin-protamine sulfate

With low APTT with thrombosis:

1. Anticoagulant therapy
2. Treatment of the underlying disease
3. Hemostasis monitoring every 3 days

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Clinical features

• APTT is most sensitive to the deficiency of factors VIII and IX
• Does not change in thrombocytopathies
• It may falsely lengthen if the blood is drawn incorrectly
• In pregnant women, it is physiologically reduced to 20-25 seconds

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Conclusions

1. APTT rate: 25-35 seconds
2. Lengthening: risk of bleeding (hemophilia, heparin)
3. Shortening: risk of thrombosis (DIC, thrombophilia)
4. Critical for:

• Preparing for operations
• Monitoring of heparin therapy
• Diagnostics of coagulopathies