Re: what is the volume of one drop blood

Kishan,

That's really a deceptively simple question, which doesn't have a 
particularly simple answer.

Assuming that by "drop" you mean either a freely-falling globule or a bit 
of blood welling up on the surface of the skin, the volume will vary 
depending on the properties of the blood itself. The viscosity, density, 
and surface tension of the fluid drop all affect its natural volume: these 
properties are related to hematocrit (the number of blood cells and 
particles in the drop), hydration levels, fluid temperature, and surface 
the drop forms upon. A discussion of fluid drop measurement techniques may 
be found at http://wso.williams.ed
u/~gsiarny/dropdet.html

When medical personnel pull "a drop" of blood for testing, they will 
usually use a pipette to draw up a pre-determined amount of blood so that 
tests can be performed uniformly. This is much more reliable than using a 
naturally formed drop.

For less-critical estimation, there is an obscure measure called a drop, 
with a volume of approximately 1/30 ml. I've never actually heard of 
anyone actually 
using it, however.

I hope this is helpful!