Endocrine Labs Flashcards
What are common signs of hypothyroidism?
Fatigue/Sluggishness Weight gain Cold intolerance Dry skin, brittle hair Constipation Slow heart/respiration Menstrual irregularities
What are common signs of hyperthyroidism?
Anxiety, irritable, difficulty sleeping Weakness in arms and legs tremors hot skin, perspiration weight loss frequent bowel movements irregular heart beat
What 5 test are used to evaluate thyroid function?
TSH Total T4 Total T3 Free T4 Free T3
Which test is used most commonly?
TSH
If TSH test results are normal, what other tests should be ordered?
None
If symptoms don’t make sense with a normal TSH result, what test should be ordered?
Free T4
What do elevated TSH levels indicate?
hypothyroidism
What do low TSH levels indicate?
hyperthyroidism
When elevated TSH results are presented, what test should be ordered and why?
Free T4
to determine the degree of hypothyroidism
When low TSH results are presented, what test should be ordered and why?
Free T4 (and possibly Free T3) to determine the degree of hyperthyroidism
What test is used to monitor therapy of patients who have hypothyroidism?
TSH
After adjusting thyroid medication, how long does it take for the TSH to equilibrate?
4-6 weeks
Time your retesting appropriately.
How do we treat a patient with hyperthyroidism?
Refer!
How do we treat a patient with hypothyroidism?
give Levothyroxine (T4)
What are Total T3 and Total T4 tests used for?
Not used often!
Measure both protein bound and unbound T3 and T4.
Both increase with hyperthyroid and decrease with hypothyroid.
What are Free T3 and Free T4 tests used for?
Confirming TSH results.
Free T3 has a more dramatic elevation than T4 in patients with hyperthyroidism.
Are Free T3 and T4 tests used to routinely monitor therapy?
Rarely.
If labs don’t make sense, such as high TSH and high FT4, what is the plan?
Problem may be in the pituitary gland. Refer!
If lab results indicate high TSH and low FT4, what is the diagnosis?
Hypothyroidism. Start Levothyroxine.
If the lab results indicate high TSH and normal FT4, what is the diagnosis?
Subclinical hypothyroidism.
Treat if the patient is symptomatic or TSH is greater than 10, or planning pregnancy.
What are the main lab tests to diagnose or screen for diabetes mellitus?
Fasting blood glucose level (FBG)
Glycosylated hemoglobin (Hb A1C)
Oral glucose tolerance test (OGTT)
Which type of diabetes is screening recommended for?
Type 2 DM
Why might a random blood glucose level be tested?
To diagnose a patient with symptoms of diabetes, if the results are greater than 200mg/dl.
When screening a patient for diabetes, and the test comes back positive, what test should be given for confirmation?
The same test you just used. Do NOT use a different test.
How well is the specificity and sensitivity of the DM tests?
Good specificity, but poor sensitivity.
Trust the positive, not the negative.
For a fasting blood glucose test, how long should the patient fast in advance?
8 hours
Can use glucose on CMP, if patient has fasted
What levels does a fasting blood glucose test confirm DM?
greater than or equal to 126 mg/dl, on TWO separate tests.
What is a normal value for fasting blood glucose tests?
less than 100 mg/dl
What is considered to be “impaired glucose tolerance?”
Patients with FBG tests between 100 and 126.
They are at risk!
How long should a patient fast for Hb A1C?
Does not require fasting.
What does the Hb A1C test reflect?
The average blood sugar levels for the 3 month period before the test.
What levels does an Hb A1C test confirm DM?
greater than 6.5% on TWO separate tests.
What are considered normal levels of an Hb A1C test?
between 5.0 and 6.0%
What Hb A1C levels indicate a patient who is at risk for developing DM?
6.0 - 6.4%
What conditions might affect the results of an Hb A1C test?
Changes to RBCs, such as anemia, chronic blood loss, toxicities, renal failure, and pregnancy.
How long must a patient fast for an Oral glucose tolerance test?
8 hours
How is an OGTT performed?
Patient first drinks 75 g of glucose solution, wait 2 hours, draw blood after 2 hours.
What levels of an OGTT test indicate diagnosis of DM?
greater or equal to 200 mg/dl
What are normal OGTT levels?
under 140 mg/dl
What OGTT levels indicate impaired glucose tolerance?
between 140 and 200 mg/dl
How is a patient with DM normally monitored?
Eye exams, Foot exams, Dental exams, monitoring Blood Pressure, Weight, Diet, Exercise, and Smoking cessation.
What lab exams are used to monitor patients with DM?
Annual urine albumin tests Annual Lipid panels Annual liver function tests (CMP) Biannual Hb A1C in stable patients (quarterly in unstable)
What does a positive albumin urine test indicate?
If patient does NOT have HTN, you should start them on an ACE inhibitor! This provides protection to the kidney!
(a patient who already has HTN should already be on an ACE inhibitor)
