There are many possible causes for a low red blood cell count (anemia). The list is too long to go over here. Instead, let’s talk about the approach I normally use in cases like yours.

My first suspicion is blood loss through the gastrointestinal tract. This is a common reason for anemia in adults over age 50. Most often, my patients need to have a colonoscopy to look at possible problems in the lower intestine. And an upper endoscopy to look at the stomach and upper intestine.

If these tests are normal, then I try to determine what the anemia is related to. It could be from:

• Blood loss from some other place in the body, such as the bladder
• Bone marrow making fewer than normal red cells, or
• Red blood cells getting destroyed prematurely

If the bone marrow is making fewer red blood cells, I first look for nutritional deficiencies. I start with ordering blood tests to see if you have enough iron and if you have enough vitamin B12 and folic acid circulating in your blood. You need all three to make red blood cells.

If the anemia is from iron deficiency, you are most likely losing blood from somewhere in your gastrointestinal tract or urinary tract. That’s because it is unusual to develop iron deficiency due to a poor diet in women of your age and men of all ages.

When the source is not seen on colonoscopy or upper endoscopy, finding the bleeding source can be challenging.

If the anemia is not due to iron, vitamin B12 or folic acid deficiency, I request that the lab perform other tests on the blood. These tests would help determine if the bone marrow no longer is producing red blood cells normally. Or if the problem is that the red blood cells are being destroyed before their normal 120-day life span.

Now I have a better picture of whether the problem is:

• Nutritional
• Blood loss from an undefined source
• Underproduction of red blood cells by the bone marrow, or
• Premature destruction of red blood cells

This allows me to narrow my search for the specific condition causing the anemia.