Hi everyone,

I have some questions about blood cell counts.

The average adult has about 10 pints of blood that the heart pumps
throughout the body.  Many blood counts in a CBC are listed as so many cells
per cubic millimeter.  Most of them are listed as K/CMM (thousand per cubic
millimeter) with the exception of the red blood cells which are listed as
M/CMM (million per cubic millimeter).

I have several medical problems including sarcoidosis and a serious T-4
lymphocyte deficiency which is not from HIV and cause unknown.  However, my
red blood cell counts in the past (4.8 - 5.0) have always been well within
the normal range (4.0 - 5.5 at my lab).  Recently I had the misfortune to
lose a lot of blood (I would guess 2 pints or more) and I had many stitches
and staples in the ER on my arms and legs (no internal injuries).

Three days before my blood loss my RBC count was 4.9.  I don't know what my
count was directly after my blood loss.  However approximately two weeks
after the incident I had a CBC and my RBC count dropped to 3.98 (just below
the lower limit), and my hemoglobin was 12.9 (near the lower limit), and my
Hematocrit was 37.6 (just below the lower limit), and my platelets were 356
(near the upper limit).  All of these counts were always normal in the past.

My main question is could my blood loss 14 days earlier account for my drop
in red blood cells and hemoglobin and my rise in platelets and how long
would it normally take for everything to return to normal.

I don't understand why blood loss would necessarily change your blood counts
per the following logic (please tell me if and why my logic is wrong).

If a person has 10 pints of blood and all the blood has the same proportions
of RBC's, WBC's, Platelets and Plasma, and you remove say 2 pints of blood,
then why doesn't the remaining 8 pints have the same proportions (this is
intuitive, at least if you had the blood in a mixing tank).

Does the red blood cell percentage decrease because they are dying off
faster trying to get oxygen from the lungs with a lesser amount of total
cells (i.e. 8 pints of blood versus 10 pints of blood being pumped
throughout the body).  It would seem to me that the cells per cubic
millimeter would remain the same unless they were dying off faster as a
result of the blood loss.  I believe
it takes about 5 days for the bone marrow to produce mature red blood cells.
I'm not sure how this figures into the equation of decreased blood cell
counts from losing blood.

My question would also apply to someone who donates a pint of blood.  Does
their RBC count go down also and how long does it take to return to normal.

I hope you all get the just of what I am asking.  Please try to explain the
logic the best you can.  Thank you.

Pete