🩸 Coagulation Testing: A Lab Overview! 🔬Coagulation tests help us assess the blood clotting process. ⚙️
I. Prothrombin Time (PT) / INR ⏳•
A. Principle: * Measures the time it takes for plasma to clot after adding tissue factor (thromboplastin) and calcium.
* Assesses the *extrinsic* and *common* coagulation pathways.
•
B. Normal Range: * PT: Typically 11-13.5 seconds (varies slightly between labs).
* INR: Ideally 0.8-1.1 in healthy individuals; 2.0-3.0 for those on warfarin therapy (target range varies based on indication).
•
C. Causes of Increased PT/INR: * Warfarin therapy (anticoagulant) 💊
* Vitamin K deficiency 🥝
* Liver disease 🤕
* Disseminated intravascular coagulation (DIC) 🩸
* Factor VII deficiency (rare)
•
D. Effects of Increased PT/INR: * Increased risk of bleeding. 🩸
* Excessive bruising. 🤕
* Prolonged bleeding after injuries. 🩹
* May require adjustments to warfarin dosage. 💊
•
E. Causes of Decreased PT/INR: * Vitamin K supplementation (can interfere with warfarin).
* Increased intake of foods rich in vitamin K. 🥬
* Conditions causing increased levels of clotting factors (rare).
•
F. Effects of Decreased PT/INR: * Increased risk of blood clots (if on warfarin). 🩸
* May require adjustments to warfarin dosage. 💊
II. Activated Partial Thromboplastin Time (aPTT) ⏱️•
A. Principle: * Measures the time it takes for plasma to clot after adding an activator (e.g., kaolin, silica) and calcium.
* Assesses the *intrinsic* and *common* coagulation pathways.
•
B. Normal Range: * Typically 25-35 seconds (varies between labs).
•
C. Causes of Increased aPTT: * Heparin therapy (anticoagulant) 💊
* Factor deficiencies (VIII, IX, XI, XII) (e.g., hemophilia) 🩸
* Von Willebrand disease 🩸
* Lupus anticoagulants 🧪
* Disseminated intravascular coagulation (DIC) 🩸
•
D. Effects of Increased aPTT: * Increased risk of bleeding. 🩸
* Excessive bruising. 🤕
* Prolonged bleeding after injuries. 🩹
* May require adjustments to heparin dosage. 💊
•
E. Causes of Decreased aPTT: * Early stages of DIC (hypercoagulable state).
* Increased levels of Factor VIII (can occur in inflammatory conditions).
•
F. Effects of Decreased aPTT: * Increased risk of blood clots (if on heparin). 🩸
* May require adjustments to heparin dosage. 💊
III. Fibrinogen Level 🍥•
A. Principle: * Measures the amount of fibrinogen (Factor I) in the blood.
* Fibrinogen is essential for clot formation.
•
B. Normal Range: * Typically 200-400 mg/dL (varies between labs).
•
C. Causes of Increased Fibrinogen: * Acute inflammation (e.g., infection, injury). 🔥
* Pregnancy. 🤰
* Certain cancers. 🦀
•
D. Effects of Increased Fibrinogen: * Increased risk of blood clots. 🩸
* May contribute to cardiovascular disease. ❤️
•
E. Causes of Decreased Fibrinogen: * Disseminated intravascular coagulation (DIC) 🩸
* Liver disease 🤕
* Congenital fibrinogen deficiency (rare).
•
F. Effects of Decreased Fibrinogen: * Increased risk of bleeding. 🩸
* Poor wound healing. 🩹
IV. D-dimer 🧩•
A. Principle: * Measures the amount of D-dimer in the blood.
* D-dimer is a breakdown product of cross-linked fibrin, indicating that a clot has formed and is being broken down.
•
B. Normal Range: * Typically < 250 ng/mL (varies between labs).
•
C. Causes of Increased D-dimer: * Deep vein thrombosis (DVT). 🦵
* Pulmonary embolism ..,....
.......(
👇👇👇👇👇
@laboratorypractice
