What's with the finger stick test when I give blood?

March 5, 2018

Every time you donate blood, we measure the level of hemoglobin in your bloodstream with a quick finger stick test.

It’s an indirect way of checking iron levels – iron is a critical component of hemoglobin – since iron helps your body replace the red blood cells lost through blood donation.

If your hemoglobin level (and, as a consequence, your iron) is too low, we’ll ask you to come back later to make a donation, just to make sure your body has the capacity to make new red cells in a timely manner.

Hemoglobin levels are measured in grams per deciliter (a tenth of a liter); the normal range for women is 12.0 to 15.5 g/dL, and for men, it’s 13.5 to 17.5. Women must have a reading of at least 12.5 g/dL and men must be at least 13.0 to be eligible to donate.

Iron levels are dependent on many factors, including age, gender, genetics and body type. 

Fortunately, there are ways to boost your iron levels. The main way is simple – eat a well-balanced diet, which includes meat and other animal products, as well as iron-fortified foods like cereal and bread. Vitamin C, found in many fruits, helps the body absorb iron.

Younger people and frequent donors also can raise their iron levels with an iron supplement.

Learn more about donating blood and schedule an appointment to give today at SouthTexasBlood.org.

More from our blog:

Cord blood treatment shows promise for treating autism

Charles Drew: Blood banking pioneer

National Donor Day is Feb. 14