A whole blood sample contains Red Blood Cells and Plasma. Hematocrit is the percent of red blood cells found in the whole blood sample.

Red blood cells carry hemoglobin which carries oxygen (fuel) to all of the cells of our body. Low hematocrit can be a reflection of decreased hemoglobin – but not always

For the purposes of screening donors for blood donation, a hematocrit level is determined in order to evaluate a donor’s general red cell status. This screening test is used to determine if a potential donor has an adequate supply of red blood cells.

Our minimum acceptable value of hematocrit is set at a level to assure that donating a unit of blood will not adversely affect the donor’s red cell status. If a donor’s hematocrit level falls below our minimum value, we are unable to collect a unit that day, so the donor is deferred.

It is important to remember that the Hematocrit reading taken at the blood bank is a “snapshot” of your red cell status at one particular moment. It is normal for hematocrit values to vary from day to day or even hour to hour.

Blood banks would not want to remove blood from a donor who’s red cells could become depleted by the donation process. We never want to jeopardize a donor’s health through the donation process. And we always want to encourage donors to try again, because we are often able to accept a donor on subsequent attempts.

When hematocrit is below pre-set parameters, it is not necessarily an indication that there is something wrong. Hematocrit can be influenced by such things as diet and hydration as well as health issues.

The hematocrit obtained during screening for blood donation is not meant to be diagnostic or predictive of any disease state. It is simply meant to reflect whether or not a person who is wishing to donate blood falls within the predetermined acceptable range.

No! Women tend to have lower hematocrit levels than men. A low hematocrit level does not mean that you are unhealthy or anemic. It is possible to be anemic and have a “normal” hematocrit. Conversely, it is possible to have an abnormal hematocrit and not be anemic.

Frequent blood donors will sometimes run a borderline low hematocrit. This may simply be a reflection of their bodies not replacing their red cells as quickly as they are being removed. Sometimes spacing donations further apart can help in this situation.

Diet can affect hematocrit and a diet high in iron can help raise hematocrit levels. Diet alone is not the only consideration, however. A prospective blood donor who eats a balanced diet and maintains good general health will not need to be overly concerned with eating high iron foods other than to help replace reserves that are depleted through blood donation.

Our final word to blood donors is this: If your hematocrit runs low and you are deferred from donating, please don’t be discouraged. Try again in a week or so! Hematocrit is only one of several tests that can determine a person’s health; high or low hematocrit on any given day may just be a natural variant in an otherwise healthy individual.

If a person consistently runs a lower than average hematocrit value, they may wish to check with their health care provider about more specific testing to see if there is a possible health issue.