High hematocrit can affect BG measurements

By WillONeil Latest Reply 2015-02-25 00:17:39 -0600
Started 2015-02-24 22:21:50 -0600

I have a fairly rare genetic condition that leads to consistently high hematocrit levels — in excess of 50 pct. When I was first diagnosed with Type 2 four months ago I was given a OneTouch Ultra2 BGMS. At first I was pleased at how easy it seemed to keep my measurements below 140 mg/dl, but soon became suspicious. Sure enough, I found that the spec upper limit of hematocrit for this BGMS is 50 pct and that at high levels it underreads BG. Not good!

Some review of the device literature showed that one inexpensive and available BGMS that is not very sensitive to hematocrit is the Bayer Contour Next. I got one and in cosampled comparisons found that its readings were an average of 21 pct higher than those of the Ultra2! I've now gotten an A1C and found that its results correlate well with the Contour Next readings.

Odds are that you don't have hematocrit levels nearly as high as mine, but if by any chance you do it's a very good idea to check whether your BGMS is affected by them and if so change to a system that isn't.

2 replies

jayabee52 2015-02-24 23:57:20 -0600 Report

Howdy Will
thanks for the heads up. I don't seem to have problems with hematocrit, but someone here may. Is your high hematocrit "ideopathic" or is there a reason you have been given for it?

I looked up hematocrit and the reasons Medline gives for high hematocrit :

"•Congenital heart disease
•Failure of the right side of the heart (cor pulmonale)
•Abnormal increase in red blood cells (erythrocytosis)
•Low blood oxygen levels (hypoxia)
•Scarring or thickening of the lungs (pulmonary fibrosis)
•Bone marrow disease that causes abnormal increase in RBCs (polycythemia vera) " source ~ http://www.nlm.nih.gov/medlineplus/ency/artic...

I wonder that if BG meters may under read your actual BG levels, would that not affect one's A1c also?

Praying for improved health for you


WillONeil 2015-02-25 00:17:39 -0600 Report

Thanks James,

It's a genetic condition that runs in the family. Since it is autosomal dominant it cannot have any major health effects, as otherwise selective pressures would have eliminated the allele for it long ago. (Actually there are four different alleles that can cause it; I haven't bothered to try to discover which one runs in my family.) It is erythrocytosis, but that tells you nothing except that my hematocrit is high. Long ago my doctor thought it might be polycythemia vera, but that was ruled out. (I'd never have lived to be 76 if it had been.) So far as my doctors can tell, my health is quite good for someone my age.

It should have no effect on A1C testing, nor on lab BGMS. The problem it causes is that the dense matrix of RBCs slows diffusion of serum electrolytes thus slowing the electrochemical reactions that the BGMS test strip measures.