endocrine labs Flashcards
Diabetes dx
-Random Blood Sugar: 200mg/dL with DM symptoms
-Fasting Blood Sugar: > or = 126mg/ dL after 8 hr fast on an Initial screening test
-Oral glucose tolerance test: glycemic response after a 75g glucose load, if 2 hrs post glucose >200 mg/dL
-HgbA1C: >6.5% -> Also used for monitoring tx
-steroid use can increase sugar
what is the initial screening test for DM?
FPG: fasting blood sugar
- Dx: >=126 mg/dL
- fast for 8h with no calories
IFG:
- 100-125
HgbA1C
-A1C: glycated hemoglobin ->RBC in a sugar bath -> saturated
-4 months
-8-12 week glucose average
Criteria for diabetes dx
- A1c >= 6.5%
OR - FPG (fasting plasma glucose) >= 126 (7mmol/L) -> 8 hours fast
OR - 2 hour plasma glucose >= 200 (11.1mmol/L) during an OGTT- 75g glucose drink
OR - in a pt with classic symptoms of hyperglycemia (requent urination, increased thirst, and unexplained weight loss) or hyperglycemic crisis, a random plasma glucose >= 200
current guidelines: how frequently do you retests pts?
Normal Sugar: Retest every 3 years
- fasting glucose <100mg/dL
- A1C <5.7%
Pre- diabetics: Retest every 1-2 years
- fasting glucose is 100 to 125 mg/dL
- A1C: 5.7-6.4 %
What should you council diabetics on?
- smoking cessation
- diet
- exercise
- intensive lifestyle counseling
categories of increased risk for diabetes: PREDIABETES
-A1C: 5.7 to 6.4%
-FPG: 100-125 (5.6-6.9)
-2 hour post load glucose on the 75 OGTT: 140-199
Ppl with impaired fasting glucose (IFG) + impaired glucose tolerance (IGT) = PRE-DIABETIC
screening DM
- Adults aged 45 years+
- persons with multiple risk factors regardless of age
point of care glucose
Finger prick: can give different results from blood draw
- not diagnostic just monitoring
- variance
Use: Monitoring before meals for dosing insulin
-Assessing for hypoglycemia or hyperglycemia
-under 126 is goal (she said this)
Hemoglobin A1C: what is it
blood test that measures the % of glucose chemically attached to Hb in RBCs:
- provides an AVERAGE of blood glucose levels over the past 2 to 3 months
- used for monitoring long-term control of blood glucose
Dx:
- HbA1c level >6.5% = diabetes
- 5.7-6.4%: pre- diabetic -> retest every 3 yrs
- use NGSP certified lab + standardized to DCCT assay
What is an early marker of nephropathy?
microalbuminuria
-early marker of nephropathy/early kidney damage
Type 1 diabetics: will have _____ and you should test for it.
Pancreatic AUTOANTIBODIES against one or more:
-for type 1 diabetes you test for autoantibodies ***
Dont need to know specific names:
-GAD65,
-IA2
-Insulin
-ZnT8
what you need to know for test
-normal
-pre-diabetes
-diabetes- 6.5 or greater
-diagnosis and target value is different for all
thyroid hormones flow chart
TRH: thyrotropin releasing hormone in Hypothalamus, induces TSH.
TSH- Thyroid Stimulating Hormone, Anterior pituitary, stimulates thyroid
T3: Triiodothyronine, Thyroid gland
- carries out majority of hormone actions
- primary feedback stimulus
T4: Thyroxine, Thyroid gland
-free T4 is what you typically order: not bound to TBG
- prohormone/active form -> T3 has much greater affinity
- T4 converts to T3 and small portion converted into reverse T3 (inactive)
- Free T4**- unbound to protein -> Better indicator of thyroid status
TBG: thyroid binding globulin:
- plasma protein for transport
What is the initial test for thyroid disease
TSH levels!!!
- inverse log-linear relationship between TSH and free T4 levels -> small changes in free T4 levels can cause significant changes in TSH levels
- ex: low t4 = HIGH TSH
Normal TSH: normal function of thyroid
Abnormal TSH:
- prompts further testing with free T4 test
What is a better indicator of thyroid status?
Free T4!!!
- unbound to protein
- not affected by changes in thyroid hormone binding proteins
continuous glucose monintor
-prevents hospitalizations
-on your body 24/7
-monitors glucose every 3 mins
-A1C monitored
-only used for injection therapy as of right now
anti-thyroid antibodies
Anti- TPO:
- Anti-thyroid peroxidase antibodies -> Antibodies against a protein in the thyroid gland that is essential for SYNTHESIZES of thyroid hormones
- indicates autoimmune thyroid disease (hypo/hyper)
- HIGH anti-TPO = HASHIMOTOS thyroiditis (90% of hypothyroid cases)
Anti- TG:
- Anti-thyroglobulin antibodies
- thyroglobulin = storage form of thyroid hormones within thyroid gland
- indicates autoimmune thyroid disease (hypo/hyper)
what is hyperthyroidism? + sx
Definition: A state characterized by excessive amounts of thyroid hormones in the body.
- Aka: Thyrotoxicosis.
Sx:
-Nervousness, palpitations
muscle weakness, heat intolerance, weight loss, perspiration
- fine tremor of hands
- sx reflect accelerated metabolic rate
-exophthalmos*
- goiter
Hyperthyroidism labs will show vs hypothyroidism labs
Hyperthyroidism:
-low TSH
- HIGH free T4 (thyrotoxicosis)
Hypothyroidism:
-Increased TSH
- LOW free T4
Diagnosis: hyperthyroidism
Initial TSH test:
- LOW TSH
- high free T4 = Primary (T4 thyrotoxicosis)
T3 thyrotoxicosis: low TSH, normal T4
- only T3 is elevated and T4 stays the same
Primary (T4 thyrotoxicosis):
- check for antibodies: GRAVES
- if no sx of graves: radioactive iodine uptake (RAIU) for toxic adenoma vs multiple adenomas vs thyroiditis (low RAIU)
HIGH TSH + HIGH Free T4 = pituitary adenoma
causes of hyperthyroidism
Graves disease: autoimmune TSH antibodies ds - antibodies stimulate the thyroid to produce too much
Toxic multinodular goiter: multiple nodules in thyroid gland
Toxic adenoma: single nodule in thyroid gland
Thyroiditis
initial screening modality for thyroid abnormality
TSH**
- check T3, T4, and antibodies if TSH is abnormal