Hb/1ac

[carolyn]

Is Hb/1ac test done with full blood or plasma? Please help me with this question. Many thanks.

[DCaplinger]

Full blood. It's a test of the glycosylated hemoglobin (red blood cells), which would not be in plasma.

Regards,

[Harold]

This plasma/whole blood is really confusing. Everything I have looked up says that meters check/read whole blood and labs are given as plasma readings. So many meter users called the manufactures and complained the manufactures figured out how to make the meters give out equivalent plasma readings from the whole blood. The confusing part of this is the lab test venous blood and meters test capillary blood. By definition Noun 1. blood plasma - the colorless watery fluid of the blood and lymph that contains no cells, but in which the blood cells (erythrocytes, leukocytes, and thrombocytes) are suspended. Now since plasma contains no cells how can testing plasma give any result of the weighted average of red blood cells? I am no medical lab tech, but my guess is they separate the red blood cells by centrifuge from the plasma. So they are not testing the current glucose or other platlets. Then they test the red blood cells for glucose from which we get a HbA1c value. Maybe a medical lab tech could clarify.

[BlueSky]

My understanding is that, when blood glucose is tested in the lab, they take the hemoglobin (red blood) cells out first. So they test for glucose dissolved into plasma. With the HBA1c test, they still separate the plasma from the hemoglobin first, and they establish the percentage of the red blood cells that are glycated (the HBA1c).

[Harold]

Usually with a HbA1c lab result you also get the Plasma Blood glucose value. So the results are the weighted percentage of glucose make up of the red blood cells and the amount of glucose per volume in the plasma. Now our meters are checking whole capillary blood which usually reads a little less than what the plasma value would read at the same time. This is a guess, but would that be because it is reading only the plasma value, but since it is in the capillaries some of it has already been absorbed by the cells the capillaries are supplying blood to? Makes sense even after some adult beverages. :cheers:

[BlueSky]

Plasma blood glucose is 12% higher than whole blood glucose simply because plasma concentrations are calculated on a smaller base. Meter readings are adjusted for this to make them comparable to lab tests. I can also see that, if blood glucose is raised after meal, capillary blood would contain less glucose than veinous blood. Glucose is being rapidly cleared out the blood stream, and the capillaries are closest to all that action. But I have no idea how much difference this might make. I suspect that if blood glucose is stable, there wouldn't be much difference.

It has just ocurred to that men have about 10% more hemoglobin than women, and I guess this gives us an unfair advantage in the meter test results game :o .