A patient with haemophilia A has factor VIII activity at 2%. The level that corresponds to severe haemophilia with spontaneous haemarthroses is:

• A Factor VIII 1-5% of normal (moderate haemophilia) ✓
• B Factor VIII <1% of normal (severe haemophilia)
• C Factor VIII 5-40% of normal (mild haemophilia)
• D Factor VIII 40-60% of normal (subclinical carrier state)

Explanation

Haemophilia A is classified by residual factor VIII activity: severe (<1%), moderate (1-5%), and mild (5-40%). A factor VIII level of 2% falls in the moderate range (1-5%), not severe. Severe haemophilia (less than 1%) is associated with spontaneous haemarthroses and life-threatening bleeds. Moderate haemophilia causes bleeding with minor trauma. Mild haemophilia (5-40%) causes prolonged bleeding only with significant trauma or surgery. Carriers have approximately 50% activity and are typically asymptomatic, though some manifesting carriers can bleed.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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