Quick facts
A1C is a 3-month average, so it doesn't replace a glucose check
Some conditions make A1C read falsely high or low
- Anything that changes how long red blood cells live, such as recent blood loss, a transfusion, sickle cell disease, or hemodialysis, can change A1C. Iron-deficiency anemia can make it falsely high, and kidney failure or liver disease can also give false results.[2]
- A hemoglobin variant, a different type of hemoglobin more common in people of African, Mediterranean, or Southeast Asian descent, can interfere with some A1C tests. Interference is suspected when the A1C and the blood glucose results don't match.[2]
A goal below 7% isn't safe for every patient
- Keeping A1C below 7% lowers the risk of complications for some people with diabetes, but that goal may not be safe if it leads to hypoglycemia.[2]
The Glucose care: clinical reasoning flashcard deck covers hypoglycemia, diabetic ketoacidosis, and hyperosmolar hyperglycemic state. Find the deck in the free app preview.
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Practice question
A nurse reviews a hemoglobin A1C of 8.1% for an adult patient with type 2 diabetes. Which statement about this result is accurate?
- A. The result shows the patient's blood glucose at the moment of the draw.
- B. The result falls in the prediabetes range for an adult patient.
- C. The result is valid only if the patient fasted for 8 hours first.
- D. The result is above the common goal of below 7% in diabetes.
Show the answer and why
Correct answer: D. The result is above the common goal of below 7% in diabetes.
- A. Incorrect. A1C is a 3-month average. A glucose check, not an A1C, shows the level at a single point in time.
- B. Incorrect. Prediabetes is 5.7 to 6.4%. 8.1% is above the diabetes cutoff.
- C. Incorrect. An A1C test needs no fasting.
- D. Correct. 8.1% is above the common goal of below 7%. A1C reflects average blood glucose over the past 3 months.
Sources for this question: [1][2][4]
Memory hook: A1C looks back 3 months: below 5.7 is normal, 5.7 to 6.4 is prediabetes, 6.5 or higher is diabetes.