Search launched for cause of high level

Dear Dr. Roach: I am a 51-year-old male in very good health. I have had blood tests taken yearly for the past 15+ years. Nearly every test shows high hemoglobin. My average is 17.4.

My primary care physician was never concerned. He said that my numbers were not much over the threshold and that as long as the numbers hold steady, there is nothing I should do.

He retired a year ago, and my new doctor is very concerned. I was sent to a hematologist. We discussed what could cause this, and ruled out everything. She ran another set of blood tests to check for genetic markers for polycythemia vera. They came back negative.

Is there any reason to keep searching for a cause when it seems I’ve exhausted the list? — L.B.

The range of “normal” values provided by the laboratory represent where 95% of people without apparent illness would be. That means 5% of healthy people will have a lab result that is outside the range.

Low hemoglobin levels, anemias, are very common, but high hemoglobin levels are much less so. An evaluation for the most common causes of high hemoglobin is reasonable, as some of them are serious.

I am surprised you did not have an erythropoietin level. A high EPO level indicates that something is stimulating your bone marrow to make more red blood cells. A low EPO level would be more suggestive of polycythemia vera.

Abnormal blood clotting is a critical issue in polycythemia vera, which is partly why it is critical to make the correct diagnosis. Deciding whether to go further in your evaluation — getting the EPO level, and if it’s low, then getting the definitive bone marrow biopsy — requires judgment. It also requires knowing how confident a patient needs to be. Some people are very uncomfortable living with uncertainty.