Lab Work Flashcards
Ferritin elevated?
Acute phase reactant, compare to Hbg is it appropriate?
RBC macrocytosis
B12/ Folate deficiency - consider chronic alcohol use
Neutrophils up but WBC normal?
Consider immunosuppression, elderly
INR?
If they are on Warfarin titrate accordingly, if elevated and not on Wafarin be very concerned - 1.5 is enough to bleed out
RF elevated?
Think connective tissue disorder
ANA elevated?
Think lupus - true lupus is an elevated RF and ANA
Anything over 1:160 is lupus, 1:80 is connective tissue and 1:320 is very very sick
Lactate vs LDH
LDH - measure of myocardial damage and hemolysis
Lactate - acidosis from metabolism
ANCA/ p-ANCA?
Tests for vasculitis
Anti ds-DNA?
Final test for lupus (antibodies to your own DNA)
Lots of IG?
Consider multiple myeloma
CK?
Muscle breakdown
Sky high testosterone/ estrogen/ DHEA?
Probably using the steroids
Hepatitis B surface Ag
Rules out active infection
Urine samples are best when?
First morning is better, no heavy work before, must test in 1 hour, 2-8C for 24 hours for CHEMICAL testing only
Low specific gravity urine?
Basically H20 - diabetes insipidus
High specific gravity for urine - diabetes Mellitus
Speckling on urine dip?
Solid RBC casts
Urine nitrites?
Are a highly specific test, but not very sensitive for UTI
Urine ketones sensitivity?
More sensitive than plasma ketones
Urine protein?
Measures albumin - need to do 24 hour screen to figure out.
Signs/ Sx of Tylenol OD
Right away no sx, N/V malaise
2-3 days, RUQ pain, change in blood chemistry - this is when the liver starts to die
After that the question is if the liver will recover or you will have liver failure
When does the Rumack- Matthew nonogram
4-24 hours for the nonogram - draw the serum Tylenol - then if risk of toxicity - give NAC (usually given IV for 24 hours) and call poison control.
Classic ASA overdose?
Tinnitus, signs of metabolic acidosis
Osmolar gap?
Looking for large molecules in the blood - toxic alcohols, mannitol, etc
How to calculate the osmolar gap
Measured - 2x Na + sticky (glucose) + BUN
Hypokalemic? What’s the first step?
Is their BP high? Or not?
If yes then it is aldosterone
If no then it is either due to high pH, high insulin or catacholemines
Or poor intake
Hyponatremia what do you have to check?
Is the glucose or TG also high? If yes then fake.
Is the serum osmolal off? If normal or high it is likely one of the two above. It needs to be low. This is in comparison to urine osmolo
Then look at the patient. Are they dry? Are they wet?
This gives volume status.
Then look at urine sodium is it high or low this will give cause.
Urine sodium is not useful when?
Diuretics, on fluids take it before
Approach to Hyponatremia
- Is it true? High TGs or Glucose
- Serum osmol - is it high, low or normal (this determines tonicity- if hypotonic get ->
- Urine osmol - high? (ADH is active), low (aldosterone is active)
- Volume status -compare urine sodium and urine osmol hypo (low sodium in urine, and high osmol (>100)) , euvolemic, hyper (low sodium in urine, high osmol), euvol- urine sodium normal, and high osmol
Remember that the urine osmol is relative to serum.
Causes of hypervol - heart failure, cirrhosis, nephrosis (you are just 3rd spacing) -
Causes hypovolemic - dehydration - give fluids, Lasix and fluid restrict.
Causes of euvolemic - SIADH, primary polydipsia, SSRI overdose, thyroid, adrenal insufficiency (AM cortisol and ACTH) - Fluid restriction
Tx of severe hyponatremia
100cc 3% NS (increase sodium by 4-5 points), repeat up to 3 times. But in real life we don’t tend to do this
- Only use of patient has a sodium less than 120 and is showing severe features, seizures.
(Ideal sodium/ actual sodium)xTBW = amount of fluids in L
Then divide by 24 hours
Be cautious - undercorrect rather than overcorrect.
Urine sodium when?
BEFORE tx hyponatremia
BUN is up rest of kidney is normal
Digesting blood. Consider GI bleed
