42 terms

Clin Diagnostics Exam III - Chemistry BMP

BUN levels indicate
how well liver is functioning and how well kidneys are excreting
critical BUN level
over 100
decreased BUN in
liver disease, fluid overload, malnutrition / malabsorption, early pregnancy, nephrotic syndrome
increased BUN in
high protein diet, UGI bleed, steroids, tetracycline, azotemia
prerenal azotemia causes
hemorrhage, shock, trauma, sepsis, high protein diet, tumors, dehydration
causes of postrenal azotemia
urethral obstruction
better measure of kidney fx than BUN
serum creatinine
why serum creatinine would be elevated
look for prerenal cause if BUN / creatinine ratio is above
complete metabolic profile includes
basic metabolic profile and liver fx tests
factors that can influence metabolic profile results
hemolysis, timing, lab error
critical serum creatinine value
critical sodium values
<120 or >160
importance of sodium
Major extracellular cation , maintains ECF (extra cellular fluid) volume
most common electrolyte disturbance in hospitalized pts
hyponatremia is asx until sodium drops below
125 mEq/L weakness
neuro sx of hyponatremia show up when levels drop below
115 mEq/L thirst hyperreflexia
predominant intracellular cation
serum potassium depends on
aldosterone, sodium reabsorption, acid base balance
aldosterone's effect on K
increases renal loss of K
effect of sodium reabsorption on K
K lost as Na reabsorbed
K levels in alkalosis
K levels in acidosis
EKG changes that correspond to K changes
hypoK - prolonged PR, depressed ST, prominent U, hyperK - wide qrs, peaked T
reasons for pseudohyperkalemia
hemolysis, tourniquet too tight, needle bore too small
major extracellular anion
chloride follows
Na (attempts to maintain electrical neutrality)
normal anion gap
8 - 12
anion gap calculation
AG= Na - Cl +CO2 (represents unmeasured anions, i.e. sulfate, phosphate, protein, organic acids not routinely measured)
majority of magnesium found in
bone (20% found in muscle)
hypomagnesia often seen in
sx of hypocalcemia
tetany, Chvostk's sign, trousseau's sign, muscle cramps, seizures, dysrythmias, prolonged QT
Chvostek's sign
tap TMJ and face twitches
Trousseau's Sign
reflexive hand spasm when BP cuff is pumped too high
glucose levels are controlled by
insulin and glucagon
indications of diabetes
fasting BS >126 on more than one occasion or random >200 once with clinical symptoms, GT testing >200 at 2 hours
Hg A1C
(screening test for diabetes) marker of glucose levels over past 3 months
Glucose tolerance test
not used in screening test - used in high risk individuals who are already suspected of having diabetes
abnormal glucose tolerance test
persistent elevated 2 hr levels (>200 mg/dL)
usual cause of hypoglycemia
insulin overdose
definition of hypoglycemia
blood sugar <50 mg/dL with symptoms
reason for fasting and postprandial hypoglycemia
fasting - pathological, postprandial - exaggerated insulin response