Hemoglobin A1c Calculator

This hemoglobin A1c (HbA1c) calculator calculates the blood sugar in mg/dL or mmol/L from the HbA1c value and it also calculates the HbA1c from either blood sugar in mg/dL or mmol/L.

HbA1c, or glycated hemoglobin, is a form of hemolgobin that is measured primarily to identify the average plasma glucose over a prolonged period of time.

The HbA1c value provides a 3-month trailing average of blood sugar.

It is used primarily for diabetics to see whether their diaabetes is well controlled.

Diabetics blood sugars can greatly fluctuate from day to day. At one monent, when their blood sugar is under control, it can be normal, between 70-110mg/dL. At other moments, they can go into a life-threatening situation called diabetic ketoacidosis (DKA) for those with type 1 diabetes or hyperosmolar hyperglycemic nonketotic syndrome (HHNS) for those with type II diabetes. In other words, blood glucose tests show a person's blood sugar at that exact moment.

A hemoglobin A1c test is unique in that it gives a long-term picture of blood sugar.

How it works is that when blood glucose is high, glucose molecules attach to the hemoglobin in red blood cells. The process by which sugar attaches to a protein by covalent bonding is called glycation. This happens without the need of any enzyme to complete the process. The longer the hyperglycemia occurs in blood, the more glucose binds to hemoglobin in the red blood cells and the higher the glycated hemoglobin (sugar-coated hemoglobin).

Once a hemoglobin molecule has been glycated, it remains so. A buildup of glycated hemogloin within the red blood cell, therefore, reflects the glucose level during the time of the life cycle of the red blood cells. Therefore, measuring glycated hemoglboin reflects on the blood sugar level that red blood cells were exposed to.

Generally, people with good control of blood sugar will have HbA1c values of 4-6%.

Any diabetic with a glucose measure under 7% is said to have good control of their diabetes. This is the target that most healthcare professionals set. Any value above 7% represents poor control of blood sugar.

This calculator calculates the blood sugar in mg/dL or mmol/L of a certain HbA1c value and it also converts a blood glucose level in mg/dL or mmol/L into the HbA1c value.

To convert a HbA1c value to mg/dL, the formula to do so is, blood sugar ( in mg/dL)= (HbA1c * 28.7) - 46.7.

Thus, as an example, a HbA1c value of 6% has a blood glucose of 125.5mg/dL, since blood glucose= (HbA1c * 28.7) - 46.7 = (5 * 28.7) -46.7= 125.5 mg/dL.

To convert a HbA1c value to mmol/L, the formula to do so is, blood glucose (in mmol/L)= ((HbA1c * 28.7) - 46.7)/18.

Thus, as an example, a HbA1c value of 6% has a blood glucose of 6.97 mmol/L, since blood glucose= ((HbA1c * 28.7) -46.7)/18= 6.97 mmol/L.

To convert from a blood sugar in mmoL/L to HbA1c, the formula to do so is, HbA1c= ((blood sugar in mmol/L * 18) +46.7)/28.7.

Thus, as an example, a blood sugar of 8mmol/L has an HbA1c value of 6.6%, since HbA1c= ((blood sugar in mmol/L * 18) +46.7)/28.7= ((8 * 18) +46.7)/28.7= 6.6%.

To convert from a blood sugar in mg/dL to HbA1c, the formula to do so is, HbA1c= (blood sugar in mg/dL +46.7)/28.7.

Thus, an example, a blood sugar of 140mg/dL has an HbA1c value of 6.5%, since HbA1c= (blood sugar in mg/dL +46.7)/28.7= (140 + 46.7)/28.7= 6.5%.

Hemoglobin A1c is a good test to measure long-term control of diabetes (3 months), but it several factors can affect and skew HbA1c results, making it inaccurate. Any conditions in which red blood cells are lost too quickly or retained too long can skew results. Red blood cells being lost quickly will result in an artificially low HbA1c value and red blood cells being retained longer than normal in the body can result in an artificially high HbA1c. So factors such as blood transfusions, hemolytic anemia, erythropoeitin treament all can skew results of HbA1c testing.

However, for all practical purposes, it is a great way to monitor long-term blood sugar control.

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