Which of the Following Features About a Thromboplastin Preparation Is

Which of the following features about a thromboplastin preparation is necessary for accurate results?

A) Serial dilutions must be made of the thromboplastin preparation and measured to create a standard curve.
B) The international sensitivity index (ISI) of the thromboplastin preparation should be close to 1.
C) The thromboplastin preparation must be made by and purchased from the International Standardization Committee.
D) The thromboplastin preparation must be tested and certified by the World Health Organization (WHO) .