Clinical Chemistry General Questions Flashcards
If you are collecting chemistry specimen which tubes should be used for serum? (2)
- Tiger Top
- Red Top
*All other tubes are plasma
This test is used to detect antigen in assay using antibodies.
Immunoassay
What are the 4 types of ELISA?
- Direct
- Indirect
- Sandwich
- Competitive
Any test result that may require rapid clinical attention is called what?
Critical value
Basic metabolic panel contains what 4 things?
- Concentration of electrolytes
- Volume status
- Acid Base status
- Baseline renal function
When looking at the BMP fish bone what 4 values are electrolytes?
Na, K, Cl, CO2
When looking at the BMP fish bone what 2 values measure renal function?
BUN, Creatinine
What is the major extracellular and intracellular electrolyte ?
- Extracellular = sodium
- Intracellular = potassium
Serum sodium levels reflect changes in what?
Water balance
Which hormone is responsible for reabsorption of sodium?
Aldosterone
Which hormone is responsible for reabsorption of water?
ADH
What are the 3 primary functions of sodium?
- Maintain osmotic pressure
- Acid base balance
- Transmit nerve impulses
What is the percentage of NaCl in the following saline solutions:
Normal
Half Normal
Hypertonic
Normal = 0.9%
Half normal = 0.45%
Hypertonic = 3%
Hyponatremia can be a result of what 3 things?
- Hypervolemia
- Hypovolemia
- Euvolemia
Hyponatremia <116 mEg/L can result in what?
neurologic defects
seizures
How should sodium be replenished and why?
Must be replenished slowly to prevent central pontine myelinolysis
If the patient presents with symptomatic hyponatremia, what saline solution is recommended?
Hypertonic saline solution
What are the 2 functions of potassium?
- Maintain intracellular neutrality
- Skeletal and cardiac contractions
How is potassium excreted and replenished?
- excreted = urine
- replenished = diet
If potassium is significantly elevated what should you consider doing and why?
A redraw as test can be falsely elevated with hemolysis
Diabetic patients need to be supplemented with insulin and what electrolyte?
Potassium
*To prevent hypokalemia
What ECG changes are seen in hypokalemia? (2)
- Flattened T waves
- Prominent U waves
What ECG changes are seen in hyperkalemia? (3)
- Peaked T waves
- Widened QRS
- Depressed ST segment
Which electrolyte complements sodium to equal out the charge?
chloride
This ratio measures the metabolic function of the liver and excretory function of the kidneys.
BUN: Creatinine ratioH
What creatinine value should caution you against administering contrast dye?
1.5
Creatinine is used to assess what 2 things?
- renal function
- GFR
Creatinine is a product of what?
muscle breakdown
A BUN:Creatinine ratio of >20:1 suggests what? (2)
Prerenal causes:
- volume depletion
- dehydration
A BUN:Creatinine ratio of <20:1 suggests what? (3)
Renal causes:
- Acute tubular necrosis
- Glomerulonephritis
- CKD
Hypoglycemia can be a result of what 4 things?
- Insuline resistance
- Starvation
- Insulinoma
- Hypothyroidism
Hyperglycemia can be a result of what 2 things?
- Diabetes
- Acute stress
Calcium can be present in the body in what 3 ways? (%)
- 15% bound to anions
- 40% bound to albumin
- 45% active free calcium
What is the equation for corrected Ca level?
(Total Ca) + [ 0.8 * (4.0- (albumin))]
What are 3 signs/symptoms of hypocalcemia?
- nervousness
- excitability
- tetany
What can cause refractory hypocalcemia?
-Hypomagnesemia
What is the most common cause of hypercalcemia?
Hyperparathyroidism
Vitamin D intoxication can result in what?
Hypercalcemia
Anorexia, nausea, vomiting, somnolence and coma can be a result of what?
Hypercalcemia
What is the equation to measure exact CreCl?
UV/P
U = 24hr urine creatinine excretion V = volume urine/ml/min P = serum creatinine
What is the Cockroft-Gault formula for men? What do you have to add to calculate for women?
[(140-age)(weight in kg)] / (72*serum creatinine)
-For woman *.85 to numerator
Creatinine clearance is a measure of what?
kidney function
What is the simple formula for serum anion gap?
Na - (Cl + HCO3)
When is a serum anion gap most commonly performed? (4)
- altered mental status
- unknown exposures
- acute renal failure
- acute illnesses
What is the possible causes of anion gap acidosis (elevated anion gap)?
- Methanol
- Uremia
- Diabetes ketoacidosis
- Paraldehyde
- Iron / INH
- Lactic acidosis
- Ethylene glycol /ETOH
- Salicylates
This means that there are more positively charged ions (acids) present in the blood than usual.
high anion gap
A high anion gap suggests what?
anion gap metabolic acidosis
T/F: You should NOT draw blood above an IV site.
True
CO2 value is a measurement of what 3 things?
H2CO3
Dissolved CO2
HCO3
Which of the volume are less specific and more sensitive to low volume states: BUN or creatinine?
BUN
what study is used to estimate GFR?
Modification of Diet in Renal Disease (MDRD) study
The formula used to calculate eGFR systematically ____________ the value in African Americans
underestimates
The data used to develop the CKD-EPI formula showed that Black individuals in the dataset had, on average, GFR levels that were ____% higher than people of other races with the same age, sex, and serum creatinine level
16%
eGFR algorithms result in _____ reported eGFR values (which suggest better kidney function) for anyone identified as black
higher
