Q: I am a 47 year old woman with thinning on the top of my scalp for three years. I think I want to go for a comprehensive evaluation for hair loss and know that the doctor may want to take blood tests to help find out the cause of my hair loss. I am not sure if I need to fast before I come in?

A: Fasting is not necessary for a comprehensive evaluation.

The comprehensive diagnosis may include hair pull tests, hair pluck, hair density measurements, anagen telogen ratios, scalp biopsies and laboratory (blood) tests but no pre-test fasting or other preparation is necessary.