Urine tests for diabetes facts
What are urine tests for diabetes?
Urine tests are tests performed in a clinical laboratory or at home using
self-test kits and a sample of the patient's urine. Urine tests can be performed
for a variety of reasons, but in people with diabetes, they are most commonly
used to look for ketones or microalbumin (see below). Urine glucose (sugar) can
also be measured, but this is less valuable than blood glucose levels for
diagnosis and monitoring of diabetes, so this is not commonly done as a way to
monitor blood glucose status.
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This test detects the presence of ketones, which are
byproducts of metabolism that form in the presence of severe hyperglycemia
(elevated blood sugar). Ketones are formed from fat that is burned by the body
when there is insufficient insulin to allow glucose to be used for fuel. When
ketones build up to high levels, ketoacidosis (a serious and life-threatening
condition) may occur.
Ketone testing can be performed both at home and in the clinical laboratory.
Ketones can be detected by dipping a test strip into a sample of urine. A color
change on the test strip signals the presence of ketones in the urine. Ketones
occur most commonly in people with type 1 diabetes, but uncommonly, people with
type 2 diabetes may test positive for ketones.
The microalbumin test detects microalbumin, a type of
protein, in the urine. Protein is present in the urine when there is damage to
the kidneys. Since the damage to blood vessels that occurs as a complication of
diabetes can lead to kidney problems, the microalbumin test is done to check for
damage to the kidneys over time.
Can urine tests be used to diagnose diabetes?
While urine tests can show signs that may signal diabetes, such as elevated sugar or ketones, the diagnosis of diabetes is made on the basis of blood tests. Urine tests may be done in some cases as back-up testing or for screening to see if blood tests should be done, but the diagnosis of diabetes is made after blood glucose testing.
When are urine tests used in people with diabetes?
The ketone test is generally recommended for people with type 1 diabetes. Those with type 1 diabetes should test their urine for ketones when they are ill, especially if they have vomiting and nausea. Pregnant women with type 1 diabetes may also be advised to test their urine for ketones. Ketone testing is also done when the blood sugar is noted to be very high (over about 240 mg/dL). Your doctor can advise you specifically about recommended testing practices for your individual situation. Sometimes, people with type 2 diabetes may be advised to check their urine for ketones. Those with type 2 diabetes should discuss with their doctor whether ketone testing is necessary and under what circumstances.
The microalbumin test is done once per year starting at the time of diagnosis in people with type 2 diabetes. Even though protein in the urine is a sign of long-term damage to the kidneys, many people have type 2 diabetes without knowing it, so it is unclear how long they have had the condition. In people with type 1 diabetes, the micoalbumin test may not be performed until the condition has been present for up to 5 years.
Medically reviewed by John A. Seibel, MD; Board Certified Internal Medicine with a subspecialty in Endocrinology & Metabolism
Medscape. Type 2 Diabetes.
Medscape. Type 1 Diabetes.