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Anemia is a common complication of end-stage renal disease (ESRD).
Anemia occurs when there is a shortage of red blood cells or when
the red blood cells are not correctly formed. In dialysis units,
anemia is usually measured by the hematocrit blood test,
which reports the percentage of the blood that is comprised of red
blood cells. Normally, a hematocrit is from 37% to 47% for women
and from 42% to 52% for men. Without interventions, a dialysis patient's
hematocrit usually stabilizes between 20-25%. At this level, most
patients tire easily and feel drained of energy. Several statistical
analyses have shown that dialysis patients have signficantly more
complications, hospitalizations, and a higher mortality rate when
their hematocrit is below 30% (approximately).
Dialysis patients experience anemia (low hematocrit) primarily
because their kidneys no longer produce adequate amounts of erythropoietin
(EPO). EPO is the principal factor that stimulates red blood cell
production in the bone marrow.
Before 1990, most dialysis patients experienced moderate to severe
anemia on a long-term basis. At that time, dialysis patients were
given frequent blood transfusions which also exposed them to possible
infection by bloodborne pathogens such as hepatitis viruses and
HIV. Today, thanks to the availability of bioengineered EPO, the
need for most transfusions has been eliminated.
With most patients now routinely receiving EPO during their dialysis
treatments, hematocrits are routinely in the range of 30-36%. The
NKF-DOQI recommended target hematocrit range for dialysis patients
currently is 33% to 36%. Most insurance companies and Medicare will
not reimburse the dialysis facilities for EPO injections when the
patient's hematocrit is above a certain number (36% approximately).
The production of healthy blood cells is also dependent on the
body having enough iron, vitamin B12, folic acid and other substances.
If a patient does not respond to EPO therapy, the most likely cause
is a deficiency of iron. For this reason, most dialysis centers
routinely monitor iron levels in the blood.
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