3 Glucose Testing and Timed Collections Free Online FlashCards

How should you choose a specimen tube for glucose testing?

Glucose may be measured in plasma or serum; use the specimen tube and collection protocol specified by the performing laboratory.

What information should be recorded on each timed glucose specimen?

Label every tube separately with the patient’s identifiers, exact collection time, and test interval, such as “fasting” or “2 hours.”

Why can delayed glucose specimen processing produce a falsely low result?

After collection, blood cells continue glycolysis and consume glucose, which can falsely lower the measured concentration.

What preparation is generally required before a fasting plasma glucose test?

A fasting plasma glucose specimen is generally collected after at least 8 hours without caloric intake; plain water is usually allowed.

Does a random glucose test require fasting?

A random glucose test can be collected without fasting.

What determines the timing of a postprandial glucose specimen?

A postprandial glucose specimen is collected at a specified interval after a meal. Follow the order for when timing begins and record meal and collection times as required.

What glucose dose is used in a common adult, nonpregnant OGTT protocol?

A common adult, nonpregnant OGTT uses 75 g of glucose, but protocols vary by test purpose, age, pregnancy status, and laboratory.

How does a pregnancy glucose challenge test differ from a diagnostic OGTT?

A glucose challenge test is an initial screen; a diagnostic OGTT is a different procedure. Pregnancy protocols and interpretation thresholds differ, so follow the ordered protocol.

Why does a gray-top tube not eliminate the need for prompt processing?

A gray-top tube commonly contains sodium fluoride and potassium oxalate, but fluoride does not inhibit glycolysis immediately; prompt processing is still important.

What should patients do about prescribed medication before glucose testing?

Patients should follow the ordering clinician’s medication instructions and should not stop prescribed medication on their own.

What dietary preparation may be advised before a diagnostic OGTT?

Preparation may include maintaining a usual diet with adequate carbohydrate intake in the days before a diagnostic OGTT; follow the specific instructions.

When is the fasting specimen collected during an OGTT?

Collect the fasting specimen before the patient drinks the glucose solution, and label it with its collection time.