JamunJar: Health & Wealth for a better tomorrow

🧪 APTT – Activated Partial Thromboplastin Time

Parameter	Details
Full Name	Activated Partial Thromboplastin Time
Sample Type	Blood (Plasma – collected in a blue-top citrate tube)
Fasting Required	❌ No
Test Type	Coagulation Test
Turnaround Time	Typically 1 working day

🔬 What Is APTT?

The APTT test measures the time it takes for blood to clot via the intrinsic and common coagulation pathways. It evaluates the function of clotting factors VIII, IX, XI, XII, and common pathway factors II (prothrombin), V, and X.

It is a critical screening test for bleeding disorders, heparin therapy monitoring, and pre-surgical risk assessment.

🧠 Organs Involved

Organ/System	Role
Liver	Produces most clotting factors
Vascular system	Site of coagulation cascade activation
Bone marrow	Produces platelets (though not directly measured by APTT)

🎯 Why Is This Test Done?

Clinical Purpose	Examples
🔍 Screen for bleeding disorders	Hemophilia A (Factor VIII), Hemophilia B (Factor IX)
💉 Monitor unfractionated heparin therapy	APTT is prolonged when heparin is active
⚠️ Pre-surgical coagulation check	To prevent unexpected intraoperative bleeding
🧬 Detect clotting factor deficiencies	Especially in congenital bleeding disorders
🔄 Evaluate liver dysfunction	As liver produces most coagulation proteins
🤰 Assess DIC (Disseminated Intravascular Coagulation)	In critical care or obstetrics emergencies

📊 Normal Range

Reference Range: 25–35 seconds (can vary slightly by lab)
Therapeutic Range (Heparin Therapy): 1.5 to 2.5 times the baseline APTT

A prolonged APTT suggests a defect or inhibition in the intrinsic or common coagulation pathways.

📉 Low APTT (Rare)

Usually not clinically significant
May indicate high fibrinogen or acute-phase reactions

📈 Causes of High (Prolonged) APTT

Category	Examples
Inherited deficiencies	Hemophilia A (Factor VIII), Hemophilia B (Factor IX)
Liver disease	Decreased synthesis of clotting factors
Heparin therapy	Inhibits thrombin and factor Xa
Lupus anticoagulant	Paradoxically prolongs APTT without bleeding
Vitamin K deficiency	Affects factor II and X (mild APTT effect)
DIC	Consumptive coagulopathy

🔁 Other Tests Often Ordered With APTT

Test	Why
PT/INR	Measures the extrinsic pathway (often paired with APTT)
Fibrinogen	Decreased in DIC or liver failure
Platelet Count	Assesses thrombocytopenia-related bleeding risks
Mixing Study	Distinguishes between factor deficiency vs inhibitor presence
Liver Function Tests	Liver's role in clotting factor production

📌 Summary Table

Test	APTT (Activated Partial Thromboplastin Time)
Measures	Time for intrinsic/common coagulation pathways to clot
Used For	Bleeding disorders, heparin monitoring, surgery prep
Organ Involvement	Liver (factor production), Vascular system
Normal Range	25–35 seconds
Prolonged In	Hemophilia, heparin use, DIC, liver disease
Complementary Tests	PT/INR, Platelets, Fibrinogen, Mixing Study

APTT

1000+ Booked this Test