Thyroid and Diabetic Testing Lecture Powerpoint Flashcards
Populations to screen for diabetes (6)
- Asymptomatic adults age 45+
- all individuals with risk factors (obese, family history)
- minority
- PCOS
- low HDL, high triglycerides
- recurrent yeast infections
HbA1C scale for diabetes
<5.7% healthy
5.7-6.4% prediabetic
>6.5% diagnostic** for diabetes
Fasting plasma glucose scale for diabetes
- 70-100mg/dL normal
- 100-126mg/dL prediabetes
- > 126mg/dL diabetes
Screening guidelines for diabetes
-symptomatic presentation (polyuria, polydipsia, weight loss) AND casual plasma glucose >200mg/dL
Fasting plasma glucose follows a ___ hour fast
8
Some conditions that can lead to elevated fasting glucose (5)
- Lab error
- corticosteroids
- excess glucagon
- B blockers
- caffeine or other drugs
Random glucose test
Done without fast, should never be >200mg/dL otherwise strongly indicative of diabetes (casual, indicates need for further testing)
Glucose Tolerance Test and what is it particularly useful in diagnosing?
- Only performed in patients who have been on unrestricted diet/physical activity for 3 days before testing, involves administration of 50-100g oral glucose administered after 10 hour fast
- Gestational diabetes
Goal of diabetic control is to limit…
….microvascular and macrovascular end organ damage
Common microvascular complications of diabetes (3) and common macrovascular ones (3)
- eye (cataracts and glaucoma)
- kidney (nephropathy)
- neuropathy
- brain (stroke)
- heart (CAD)
- extremities (peripheral vascular disease)
HbA1C testing
Measures 70% of glycosylated hemoglobin in blood which remains for the 120 day lifespan of the RBC (avg) (does not reflect acute increase or decrease) and therefore allows for highly accurate measure of blood glucose conc.
__% change in A1C reflects a change of about ___mg/dL in avg blood glucose
1, 30
Conditions that alter HbA1C (4)
- Iron deficiency (increased)
- sickle cell (decreased)
- bleeding (decreased)
- toxicity (increased)
Creatinine levels and diabetes
Increased suggest presence of diabetes, low is not common and not a concern unless pregnant when it should be lower (if not then cause for concern)
Microalbumin and microalbumin/creatinine ratio (and what should healthy value be?)
- Microalbumin test is an early indicator of kidney failure (albumin produced in liver and should not be present in blood when kidneys functioning properly) requiring 24 hour urine collection
- Microalbumin creatinine ratio is close to a 24 hour microalbumin test regarding accuracy without requiring 24 hour collection and is thus preferred (<30:1 ratio)
How often is microalbumin/creatinine ratio ordered in diabetic patients?
Annually
Magnesium levels in diabetic patients
-often decreased, low levels accentuate insulin resistance and exacerbate the cardiovascular risks
When is an insulin levels ordered? (3)
- evaluate PCOS
- diagnose insulinoma
- Determine cause of hypoglycemia (order alongside c peptide to monitor endogenous insulin levels)
Conditions with elevated insulin levels (4)
- cushing syndrome
- drug causes such as corticosteroids, levodopa, contraceptives
- obesity
- early type 2 diabetes
Conditions with decreased insulin levels (2)
- type 1 diabetes and late stage type 2
- hypopituitarism
Why order a c peptide level in suspected diabetic patient?
Monitor insulin production by the B cells of the pancreas to determine the cause of hypoglycemia - see if body producing enough of own insulin and are insulin resistant or not
C peptide levels in type 1 vs type 2 diabetics
C peptide level will be zero in type 1 diabetics (not producing insulin), in type 2 if left uncontrolled over time will drop to zero
Actions of thyroid hormone (6)
- Increase body’s metabolic rate and O2 consumption
- calorigenic effect increasing heat production
- increase heart rate and contraction strength
- increase respiratory rate
- stimulate appetite and breakdown of carbs, fats, proteins
- turn on and off various nuclear receptors
What do the C cells (parafollicular cells) of the thyroid produce?
Calcitonin
