CHAPTER 8 Endocrine System^367
with risk factors for diabetes, and pregnant women to ascertain their risk for gesta-
tional diabetes.
Before the test—Explain to the patient the need for a 12 hour fast prior to the test
and water only throughout the test.
Growth Hormone (GH),
(Somatotropin) Test
A growth hormone test measures the level of GH in the blood and is part of the
diagnostic workup for identifying the cause of abnormal GH production. It is per-
formed to diagnose diminished or excessive growth, immature puberty, and pitu-
itary abnormalities. Testing usually involves either a GH stimulation test or a GH
suppression test to track GH levels over time.
Before the test—Explain to the patient that stress, exercise, and low blood sugar
may increase the level of GH. Instruct the patient to fast for 10–12 hours..
Glycosylated Hemoglobin
(Hgb A1C) Test
This test measures the amount of sugar that is attached to the hemoglobin in red
blood cells. Because red blood cells live in the bloodstream for 100–120 days, the
Hgb A1C test shows the average blood sugar level for the past several months.
The test is done to evaluate the effectiveness of long–term diabetes management.
Before the test—Explain to the patient that the test is not affected by recent food
intake, medication or exercise.
Luteinizing Hormone (LH)Test
This test measures the amount of LH in a sample of blood or urine. It is done
to evaluate reasons for infertility, menstrual problems, precocious puberty and
delayed puberty.