EXAM 4 - Introduction to Clinical Chemistry Flashcards
Define clinical chemistry.
Qualitative (what?) and quantitative (how?) analysis of the components found in the bodily fluids
* blood and urine
In vitro analysis of biomarkers in blood and urine
Define clinical chemistry.
Qualitative (what?) and quantitative (how?) analysis of the components found in the bodily fluids
* blood and urine
Explain the significance of studying clinical chemistry.
Monitor changes to:
* diagnose a disease
* measure patient response to drug therapy
* analyze toxicities in clinical trials (during drug development)
* predict disease onset (ex: high glucose in blood –> diabetic/pre-diabetic
Define biomarkers.
Any substance that can be used as an indicator of a biological state.
* ex: glucose, ions, proteins, hormones, lipids, metabolites, genes
Describe the purpose of disease-related biomarkers.
- Identify threat of potential disease (indicator or predictor genes –> indicates potential development of disease)
- Identify present disease state (diagnostic)
- Development and progression of disease (prognostic)
Explain the mechanism of glucose and glucose meters.
Glucose meters use electrochemistry to quantify glucose.
* glucose –> gluconic acid = produces H2O2
* H2O2 is used to convert ferricyanide to ferrocyanide (reversible reaction)
* ferrocyanide –> ferricyanide = produces measurable electric current
Describe the electrolyte profile.
Common test to determine concentrations of Na+, K+, Cl-, and HCO3-
* measured with Ion Selective Electrodes (pH meter)
What are Ion Selective Electrodes used for?
To determine how many electrodes are present.
* ex. you can use a Na+-selective pH meter to measure the amount of Na+ present.
Acid-base homeostasis (blood pH) is intimately controlled by levels of ___.
circulating oxygen and carbon dioxide.
What is the dynamic equillibrium that maintains acid-base homeostasis in the blood?
CO2 + H2O <-> H2CO3 <-> HCO3- + H+
What is the difference between metabolic and respiratory acidosis/alkalosis?
Respiratory - effects levels of CO2
Metabolic - effects levels of HCO3-
What is the difference between metabolic and respiratory acidosis/alkalosis?
Respiratory - effects levels of CO2
Metabolic - effects levels of HCO3-
Explain what is expected with respiratory acidosis.
Impaired CO2 elimination from the lungs.
* increase of CO2
* pushes equation to the right
* more protons produced to balance equation
* result: acidic
Explain what is expected with respiratory alkalosis.
Increased rate of respiration (elimination of CO2)
* less CO2 –> less H+ protons
* result: alkalosis (basic)
Explain what is expected with metabolic acidosis.
Bicarbonate deficiency –> anion gap
* reduced acid excretion –> acid production exceeds acid elimination
* increased acids = increased H+ protons = decreased amount of bicarbonate
* result: increased anion gap (AG)
Explain what is expected with metabolic alkalosis.
Excess of bicarbonate ion
* result: depletion of H+ protons
What is the formula to calculate the anion gap?
AG = [NA+] - [Cl-] - [HCO3-]
What is the ratio of cations to anions at blood’s normal charge?
total anion = total cation
* charge is neutral
What anion gap value is considered normal?
12 nM
What is a high anion gap predictive of?
Metabolic acidosis
* because HCO3- concentration is low –> when you plug into AG formula = larger number
Describe how enzymes are used to identify which tissues/organs are damaged.
Enzymes are usually cystolic and membrane-bound (not found in the bloodstream)
* when cells are damaged, their membrane becomes compromised and “leaky”
* enzymes leak from the cell to the blood stream
* you can measure activity of functional enzyme and correlate to amount
Describe what can be concluded from analysis of renal function.
renal function - eliminate produces of cellular metabolism
* high levels of urea or uric acid = low renal function
* creatinine clearance = GFR
Explain the process of measuring how much creatinine is present in the plasma.
Jaffe Reaction
* creatinine reacts with picrate (yellow) to produce a complex structure (red)
* more creatinine = higher absorbance (more red)
What is the purpose for measuring lipid levels?
High levels of lipids can be predictive or diagnostic for coronary heart disease
* measured through coupled enzyme assays
