A medical scientist is studying clotting in two patients, one with hemophilia and another without. Identify which patient is which and explain what mechanism is defective in the hemophiliac. A test was also done with a clotting factor added to the blood of patient 2. This factor is often deficient in hemophiliacs and activates other clotting factors to speed clotting. Clotting scores (relative units) are shown below.

10 min

Patient 1 min 2 min 3 min 5 min

1

50

0

75

85

0

85

99

2

98

1

2

2+factor

0

48

74

98

99

1 answer

Patient 1 is the one with hemophilia, as their clotting scores are much lower than patient 2's scores. The mechanism that is defective in hemophiliacs is the lack of a specific clotting factor, known as factor VIII or factor IX, depending on the type of hemophilia. These factors are crucial for the activation of other clotting factors in the coagulation cascade.

When the clotting factor was added to patient 2's blood, their clotting scores improved significantly, demonstrating the importance of this factor in the clotting process. This factor is often deficient in hemophiliacs, leading to prolonged bleeding times and difficulty forming stable blood clots.