Fructosamine is formed in dogs’ and cats’ (and people’s) livers by combining the protein albumin with a molecule of glucose. Fructosamine is formed in proportion to glucose levels: pets with unregulated diabetes mellitus have high glucose levels, and, thus, have high fructosamine levels.
Fructosamine production doesn’t fluctuate with minute-to-minute blood sugar levels, rather it reflects a glucose-level average for the preceding two to three weeks.
Hemoglobin A1C, also called glycated hemoglobin or glycosylated hemoglobin or HbA1c, is used in people to determine diabetes regulation and test results reflect the quality of glucose control for a two to three month time period.
Hemoglobin A1C is not used in veterinary medicine because HbA1c test results correlate poorly with dog and cat diabetes management. Conversely, fructosamine is useful in people in certain circumstances (acute bleeding and hemodialysis patients), but is not used as a first-line tool.
Fructosamine measurement in healthy, non-diabetic dogs and cats, as well as pets under good control of their diabetes, should be between 142 and 450. It is reported in micromoles per liter of serum.
Please note that these numbers reflect glucose control, but not glucose level. In other words, normal blood glucose should be between 64 and 170 and is reported as milligrams per deciliter of serum. Be careful to keep these terms straight when discussing diabetes control with your pet’s doctor.
Fructosamine is measured by obtaining a blood sample from your pet. Serum is extracted from the sample, and submitted to a laboratory. Results are available in 1-2 days.
Fructosamine alone is not sufficient to regulate a diabetic dog or cat. It is, however, an excellent tool to determine whether the dosage of insulin is correct, along with the glucose curve. HbA1c in people, and and fructosamine in both people and pets, are both designed to be a proportional proxy for a patient’s glucose averages. Unfortunately, there is information on the Internet that disparages the value of fructosamine in pets. However, here are two links for valuable information that reliable as of this writing: http://www.petdiabetes.com/ and http://partnersah.vet.cornell.edu/pet/fhc/diabetes .
See you Monday, Dr. Randolph.