how many mL of blood are you going to extract if the patient has taken antibiotics?

Question

please answer if you really know

Answer 1

That would depend on what the blood are for. For example bedside blood sugar test just requires a drop of blood or two. For routine laboratory investigations it may range from 2 ml-10 ml or more (sometimes 0.5 ml or 1 ml may suffice for simple tests).

Single investigations may require 0.5 ml - 5 ml. Blood cultures as well as some toxicology tests may require 10 ml of blood. There are some blood tests as well that requires the exact amount strictly as indicated on the label of the collection tube.

Testing to get baseline information on health and nutritional status of the population may require quite larger volume of blood - more than 100 ml for an adult and amounts varies per age range.

The amount to be extracted varies. You should had specified what they are for.

Answer 2

I don't see how antibiotics have anything to do with how much blood is drawn.

Draw whatever amount is required for the given test.