Chemistry Set 1
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A three-hour glucose tolerance test includes a fasting blood glucose after which a specified amount of glucose is ingested. Blood specimens are then collected at one, two, and three hours for a total of four blood specimens.
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Fibrinogen is only found in plasma. It is absent in serum because it is consumed during the clotting process. Fibrinogen present in plasma would form a band between the beta and gamma globulins. Electrophoresis separates the serum proteins into four bands, which from the anodal end are: albumin, alpha, beta, and gamma globulins.
Respiratory acidosis is associated with:
Normal pH High pH Decreased pCO2 Increased pCO2
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Obstructive jaundice, also called posthepatic jaundice, is associated with an obstruction located after the conjugation of bilirubin in the liver. Laboratory results in this condition usually include: increased conjugated bilirubin, normal unconjugated bilirubin, decreased or negative urobilinogen, and pale stool color. The pale stool color is very indicative of obstructive or post-hepatic cause since normal feces get their color from bile pigments, which are not incorporated into the stool if they are obstructed. In our case, the patient's Total Bilirubin is elevated 3.0 mg/dL (reference range: 0.2 - 1.0 mg/dL) and Conjugated Bilirubin is also elevated 1.2 mg/dL (reference range: 0.0 - 0.2 mg/dL).
The formula for conversion of hemoglobin A1C (HbA1C) to glucose in mg/dL is eAG = (28.7 x A1C) - 46.7. The HbA1C measured on a patient is reported as 7.5%. What would be reported as the estimated average glucose (eAG) for this % A1C (rounded to the nearest whole number)?
142 mg/dL 169 mg/dL 200 mg/dL 262 mg/dL
What weight of H2SO4 is contained in 200 mL of a 4 molar H2SO4 solution? (Atomic weight: H= 1; S = 32; 0 = 16)
78.4 g 156.8 g 39.2 g 15.68 g
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A dilutional effect caused by the sample being hemodiluted, would not cause high serum electrolyte values since they have been diluted out. The anion gap could remain the same or become decreased. Finally, the electrolyte concentrations could not remain the same, since there will be a smaller amount in the sample to test due to the diluent.
Which of the following drug examples would be a good candidate for therapeutic drug monitoring (TDM)?
A drug that is readily cleared A drug that has a narrow therapeutic window A drug that has a wide therapeutic window A drug that is used for short-term therapy
Which of the following is true concerning atherosclerosis?
Atherosclerosis is the same as arteriosclerosis. Atherosclerosis is the deposition of plaques containing cholesterol and lipids on the innermost layer of the walls of large and medium-sized arteries. Atherosclerosis is the main outcome that is assessed in risk marker studies. Most humans do not have significant atherosclerosis.
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AFP is one of the oncofetal proteins which are produced in high concentration during fetal life. AFP is produced by the fetal yolk sac and liver. Oncofetal proteins usually disappear or are reduced to very low concentrations after birth. Increased alpha-fetoprotein levels in adults is usually associated with hepatocelluar carcinoma, as it is a tumor maker in this population. Alcoholic cirrhosis, megaloblastic anemia, and mutliple myeloma would not cause an increase in serum AFP.
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Acute phase proteins are a large group of glycoproteins found in the blood that are not related to immunoglobulins. Most of them are produced in the liver by hepatocytes in response to tissue damage or inflamation. Those acute-phase proteins whose plasma concentrations increase, in response to inflamation, are also known as positive acute-phase proteins. If their plasma concentration decrease due to inflamation, they are known as negative acute-phase proteins
Which one of the following usually shows a decrease during an acute phase response?
Albumin Alpha-1- Antitrypsin Fibrinogen Ceruloplasmin
An automated method for measuring chloride which generates silver ions in the reaction is called:
Amperiometric-coulometric titration Potentiometry Chromatography Polarography
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Amperiometric-coulometric titration operates on the principle of Faraday's law in which a silver anode releases silver ions (titration) at a constant rate when a constant potential is applied. The silver ions react with chloride in a fixed volume of solution to form silver chloride. The time it takes for the chloride in the unknown solution to react with the silver ions is proportional to the chloride activity in the sample.
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Beer's law is based on the fact that absorbance is directly proportional to the concentration of a solution. Therefore, stray light within an instrument can alter the absorbance results in this type of assay.
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CK-MB would be abnormal in cases of cardiac ischemia since CK-MB is released in higher amounts from cardiac muscle when the heart is damaged or overworked due to various conditions. All the other statements are correct about CK-MB.
Which of the following serum constituents is unstable if a blood specimen is left standing at room temperature for eight hours before centrifugation and processing?
Cholesterol Triglyceride Creatinine Glucose
Which one of the following serum constituents is increased following strenuous exercise:
Creatinine Total lipids Sodium Iron
Which of the following is found in plasma but absent in serum?
Proteins Fibrinogen Electrolytes Gamma globulin
Which of the following methods would be employed to collect sweat for chloride analysis:
Electrophoresis Counter electrophoresis Iontophoresis Isoelectric focusing
All of the following hormones are produced primarily in the pancreatic islets EXCEPT which one?
Gastrin Glucagon Insulin Pancreatic polypeptide
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Glucose is utilized by red blood cells even after blood collection. Therefore, the glucose levels will decline over time if left standing for extended periods of time. Glycolysis reduces serum glucose at a rate of 5% to 7% per hour (5-10 mg/dL) in normal uncentrifuged coagulated blood stored at room temperature. The blood should be centrifuged and the cells and serum separated within two hours of collection in order to prevent changes in serum constituents.
Which of the following is the most common technique that is used by clinical laboratories for therapeutic drug monitoring?
Immunoassay Electrophoresis Atomic absorption Ion selective electrode voltimetry
Acute phase proteins generally fall into which category?
Glycoproteins Immunoglobulins Lipoproteins Microglobulins
All of the following statements concerning CK-MB (CK-2) are true EXCEPT
Greater than 5% or 10 IU/L followed by an LDH-1: LDH-2 flip is specific evidence of myocardial infarction (MD). CK-MB levels can be normal with an elevated total CK. CK-MB and troponin levels can be elevated after an AMI. CK-MB levels are normal in cardiac ischemia.
Increased concentration of alpha-fetoprotein (AFP) in adults are most characteristically associated with:
Hepatocellular carcinoma Alcoholic cirrhosis Megaloblastic anemia Multiple myeloma
a low CSF glucose level is associated with all the following except:
Hyperglycemia Fungal meningitis Amebic meningitis Trichinosis meningitis
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Immunoassay is the most common technique that is used by clinical laboratories for therapeutic drug monitoring (TDM). Most of the drugs commonly assessed with TDM can be measured on analytical platforms which utilize antibodies (in some form) for detection. Antibodies can be developed that recognize drugs. Although most drugs are much too small to evoke an immune response, scientists can conjugate drugs to immunogenic proteins to produce antibodies that recognize drug-specific epitopes.
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In hyperglycemia you would expect a normal or elevated CSF glucose level. A decreased (low) CSF glucose level,can be found in cases of acute bacterial, fungal, amebic, and trichinosis meningitis, as all these organisms consume the glucose in CSF.
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Iontophoresis is the gold standard for the collection of sweat for sweat chloride analysis. Pilocarpine iontophoresis actually stimulates the production of sweat, which is absorbed within a gauze pad which was previously weighed dry. The sweat sample is weighed to determine how much sweat was collected. Finally, the sweat sample is analyzed for its concentration of chloride. This particular test is utilized very commonly for the screening of cystic fibrosis since these patients typically exhibit higher levels of sweat chloride. In children over the age of 6 months to adults, the reference ranges are: Equal to or less than 39 mmol/L = Cystic Fibrosis is not likely to be present (rules-out CF) 40 - 59 mmol/L = Intermediate Level (Cystic Fibrosis may be present, further testing required) Greater than or equal to 60 mmol/L = Cystic Fibrosis is most likely present
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Judging by the pH, which is acidic, this patient is experiencing acidosis. Recall that the reference range for blood pH is 7.35-7.45. The patient's carbon dioxide (pCO2) level is increased while the bicarbonate (HCO3-) level is still within reference range. This indicates that the acidosis is respiratory in nature. The fact that the bicarbonate is not increased in response to the increase in acid, indicates that the respiratory acidosis is uncompensated. Reference Range Recap: pH = 7.35-7.45 pCO2 = 35-45 mm Hg HCO3- = 22-29 mmol/L pO2 = 85-105 mm Hg
in a normal csf the protein concentration as compared to that in the plasma is generally:
Less than 50% Less than 30% Less than 10% Less than 1%
A young man is experiencing difficult breathing after fainting. The physician orders an arterial blood gas analysis which shows the following results: pH = 7.25 pCO2 = 62 mmHg pO2 = 70 mmHg HCO3- = 23 mmol/L Which condition is most likely afflicting this patient?
Metabolic alkalosis Metabolic acidosis Respiratory alkalosis Respiratory acidosis
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Lithium is commonly used in the treatment of manic depressive patients. Lithium exerts a dual effect on receptors for the neurotransmitter glutamate; acting to keep the amount of glutamate active between cells at a stable, healthy level, neither too much nor too little. This allows for a mood stabilization for these patients.
Which of the following would most likely occur as the result of hemodilution:
Low serum electrolyte values High serum electrolyte values Increased anion gap Electrolyte concentrations would remain the same
The ultimate end product of both epinephrine and norepinephrine metabolism is:
Metanephrine Vanillylmandellic acid (VMA) Homovanillic acid (HVA) Cortisol
which of the following is used primarily for the treatment of manic-depression
Phenobarbital Lithium Digoxin Ascorbic acid
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Reduced renal blood flow causes a small increase in serum creatinine. The other analytes mentioned stay the same or decrease after strenuous exercise.
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Respiratory acidosis occurs when the lung's ability to remove carbon dioxide is decreased, resulting in increased blood pCO2 and acidosis.
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The deposition of plaques containing cholesterol and lipids on the innermost layer of the walls of large and medium-sized arteries is the defintion of atherosclerosis. Arteriosclerosis is a more general term that describes a thickening and loss of elasticity of the walls of the arteries (hardening of the arteries). Atherosclerosis is a type of arteriosclerosis but is not synonymous with it. Atherosclerosis is not the most common outcome for risk marker studies because it can be hard to measure. Infarcts, cardiac procedures, death, and 'events' are more common. Most humans have visible or measureable atherosclerosis by early middle age.
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The eAG for a HbA1C of 7.5% would be reported as 169 mg/dL. Remember, the formula for conversion of HbA1C to glucose in mg/dL is eAG = (28.7 x A1C) - 46.7. So, in this case, the calculation is: eAG = (28.7 x 7.5) - 46.7 = 168.55 mg/dL or 169 mg/dL if rounded to the nearest whole number.
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The proteins found usually in plasma are the same ones as the ones found in CSF, except that in CSF the protein levels are much much lower. Normal ratio of plasma to CSF protein is about 200 to 1, or less than 1%. Elevation of CSF total protein is a nonspecific finding, but usually indicates some type of disease involving the brain or meninges. Contamination of CSF with blood due to events such as traumatic tap can elevate the CSF protein levels.
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Vanillylmandelic acid (VMA) is a metabolite of the catecholamines epinephrine and norepinephrine. VMA is found in the urine, along with other catecholamine metabolites, including homovanillic acid (HVA), metanephrine, and normetanephrine. Urinary VMA is elevated in patients with tumors that secrete catecholamines.
A patient presents with the following test results: Total Bilirubin: 3.0 mg/dL Conjugated Bilirubin : 1.2 mg/dL Urine urobilinogen: decreased Stools color: clay colored The MOST probable cause is:
Viral infection of liver Chemical damage to liver Obstructive jaundice Hepatitis
