What vitamin is essential for normal synthesis of prothrombin ...

[khang]

What vitamin is essential for normal synthesis of prothrombin group proteins, thus enabling them to bind Ca2+?
 
  a. Vitamin K
  b. Vitamin B12
  c. Vitamin C
  d. Vitamin D

Question 2

Absence of D dimers is useful for ruling out:
 
  a. Deep venous thrombosis
  b. von Willebrand disease (VWD)
  c. Protein C deficiency
  d. Factor VII deficiency

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Answer to Question 1

ANS: A
Vitamin K is necessary for carboxylation of glutamic acid residues on the precursor prothrombin group proteins. This carboxylation results in the ability of these proteins to bind Ca2+.

Answer to Question 2

ANS: A
The D dimer is a specific marker for thrombosis; when the assay is negative, it is useful for ruling out DVT. (A positive result does not rule in DVT because D dimers are increased in many situations.)

[khang]

Thanks for the timely response, appreciate it

[cpetit11]

Excellent