2S [LEC]: Laboratory Assessments Flashcards
If excess is suspected, what type of dynamic function test is done?
Suppression
If deficiency is suspected, what type of dynamic function test is done?
Stimulation
In the diagnostic test for GH insufficiency, the patient is at a complete rest for how long before blood collection?
30 mins
Best specimen for diagnostic test for GH insufficiency
Fasting serum
Screening test for GH insufficiency
Physical activity test/ exercise test
Confirmatory test or gold standard for GH insufficiency
Insulin tolerance test
Normal pituitary response to insulin stress test
GH: >6 ug/L
Cortisol: >500 nmol/L
Screening test for acromegaly
Somatomedin C or Insulin-Like growth factor-1 (IFG)
Confirmatory test for acromegaly
Glucose Suppression Test/ OGTT
Differentiates secondary and tertiary hypothyroidism
Thyrotropin releasing hormone (TRH) Stimulation Test
In hyperthyroidism, what will be the level of TRH in Thyrotropin releasing hormone (TRH) Stimulation Test?
Flat (<2 mU/L)
In hypothyroidism, what will be the level of TRH in Thyrotropin releasing hormone (TRH) Stimulation Test?
Exaggerated response (>25 mU/L)
Used in the diagnosis of combined pituitary-thyroid disorders
Thyrotropin releasing hormone (TRH) Stimulation Test
Assesses hypogonadism
GnRH test
T/F: GnRH test can be done together with anterior pituitary function test
True
Between LH and FSH, which hormone will be normally markedly increased in GnRH test in adults?
LH
Between LH and FSH, which hormone will be normally markedly increased in GnRH test in children?
FSH
Gold standard for the diagnosis of diabetes insipidus
Overnight water deprivation test/ concentration or dehydration test
In overnight water deprivation test, what is the ideal start time?
10 PM
How long is the WDT usually done?
8 hours
Normal serum osmolality
275-295 mOsm/kg
Normal urine osmolality
300-900 mOsm/kg
Increased serum osmolality is an indication of what condition?
Diabetes insipidus
Produced by the liver and to a lesser degree by skeletal muscles, primarily in response to growth hormone (GH) stimulation
Somatomedin C
Somatomedin C helps doctor evaluate whether a person is producing a normal amount of which hormone?
Growth hormone
Deficiency in this hormone can lead to lack of responsiveness to GH
IGF-1
Screening test for adrenal insufficiencies
Cosyntropin test/ Tetracosactide test/ ACTH stimulation test
ACTH dose in Tetracosactide test
250 ug IV, IM
Confirms borderline response to ACTH stimulation test
Insulin tolerance test
Gold standard for secondary adrenal insuficiency
Insulin Tolerance Test
Used for the diagnosis of medullary carcinoma of the thyroid
Pentagastrin Stimulation Test
A malignancy of the calcitonin-secreting cells of the thyroid gland
Medullary carcinoma of the thyroid
Calcium level in patients with medullary carcinoma of the thyroid
Low (due to elevated calcitonin level)
Sensitive indicator of endogenous cortisol
Urine free cortisol (UFC)
Normal cortisol seen in urine
<2%
Measures the amount of cortisol in the urine
Urine free cortisol (UFC)
Plasma aldosterone level in saline suppression test if the patient has primary hyperaldosteronism
> 10 ng/dL plasma aldosterone
Plasma aldosterone level in saline suppression test in normal patient
<5 ng/dL plasma aldosterone
