Chem TB Flashcards Unit 4

1)  In uncontrolled diabetes mellitus, excess ketones are present in the blood and urine because of: / increased breakdown of lipids (lipolysis).
2)  Glucagon is made by the -cells in the pancreas and when released causes elevated blood glucose. By what mechanism does glucagon promote hyperglycemia? / Glucagon stimulates glycogenolysis and gluconeogenesis.
3)  What is characteristic of type 1A diabetes mellitus? / Circulating autoantibodies formed against pancreatic insulin-secreting cells.
4)  Glycated hemoglobins are formed by the addition of glucose to the ___-terminal _____ residue. / N; valine
5)  Determining urinary albumin excretion (UAE) is critical in type 1 and type 2 diabetics because: / increased UAE is highly predictive of and is thought to precede diabetic nephropathy and end-stage renal disease.
6)  The role of the clinical laboratory in diagnosis of diabetes mellitus involves initial diagnostic criteria. For many years, the only diagnostic criterion required was demonstration of hyperglycemia in two or more fasting plasma glucose tests. What other laboratory analysis is now considered to be useful as a diagnostic criterion? / Demonstration of elevated hemoglobin A1c
7)  The syndrome that is considered a collection of associated clinical and laboratory findings that include insulin resistance, hyperinsulinemia, obesity, high triglyceride and low high-density lipoprotein (HDL) cholesterol, and hypertension is the: / insulin resistance syndrome.
8)  Type 2 diabetes mellitus: / is associated with resistance to the action of insulin.
9)  A pregnant woman at 27 weeks gestation is screened for gestational diabetes mellitus. Plasma venous glucose was measured at 1 hour following a 50 g oral glucose load. What value must this glucose be above or equal to for a glucose tolerance test to be performed? / The value must be 140 mg/dL glucose.
10) Insulin regulates blood glucose levels by: / stimulating the translocation of a glucose transporter and promoting glucose uptake into skeletal muscle and fat.
11) Factors identified as associated with (and possibly causing) type 1 diabetes mellitus include all of the following except: / insulin resistance.
12) A woman visits her physician with a complaint of polyuria and polydipsia. She has a family history of type 2 diabetes mellitus and is concerned that she is developing the disease. The physician notes that her previous hemoglobin A1c (Hb A1c) value was 6% (considered within healthy reference interval in the physician’s practice) with a fasting plasma glucose of 95 mg/dL. At this visit, her Hb A1c value is 8.5%. Why would the physician be correct to order an oral glucose tolerance test (OGTT) for this individual? / The Hb A1c result indicates an increase in average blood glucose and possible
onset of type 2 diabetes. An OGTT would help to confirm this.
13) Hb A1c makes up approximately what percentage of total Hb A1? / 80%
14) Retinopathy, neuropathy, microvascular, and macrovascular changes are all chronic complications of both type 1 and type 2 diabetes mellitus. One theory as to the cause of these chronic problems is the elevation of advance glycation end (AGE) products. These AGE products consist of: / proteins that have been irreversibly modified by nonenzymatic attachment of glucose.
15) Insulin deficiency in diabetes mellitus will cause: / increased glucagon concentration, which contributes to hyperglycemia and ketosis.
16) What 2-hour plasma glucose oral glucose tolerance test (OGTT) results would be classified as diagnostic for impaired glucose tolerance if an individual’s fasting blood glucose value is 120 mg/dL (healthy glucose reference interval is 74 to 99 mg/dL)? / 195 mg/dL
17) A fingerstick glucose value was 120 mg/dL. If unhemolyzed serum or plasma were tested from the same individual at the same time, what might the glucose value be? / Approximately 132 mg/dL
18) The development of ketoacidosis in an uncontrolled diabetic is caused by the: / increased formation of -hydroxybutyric acid.
19) An individual with a severe, uncontrolled case of type 1 diabetes mellitus will exhibit all of the following laboratory results except: / hyperinsulinemia.
20) As a counter-regulator of glucose metabolism in a healthy individual, epinephrine has the effect of _____ blood glucose. / stimulating glycogenolysis to increase
21) High albuminuria is defined as: / increased urinary albumin excretion between the range of 20 to 200 µg/min that is measured by the laboratory in the chronic management of diabetes mellitus.
22) Although not a routine clinical laboratory screening test, measurement of insulin secretion in a potential diabetic is important because: / a decrease in glucose-stimulated insulin secretion is the first functional abnormality in both types of diabetes.
23) The hyperglycemia observed in a diabetic causes many toxic effects such as retinopathy and nephropathy. Although it is unclear how these outcomes are caused by elevated blood sugar, it is thought that hyperglycemia: / causes increased production of advanced glycation end products, which might contribute to microvascular complications.
24) What antibodies is found most commonly in over 90% of children who develop type 1 diabetes before 5 years old? / Insulin autoantibodies
25) What cardiac biomarkers is elevated about 50 times the upper limit of normal at 24 hours after onset of an acute myocardial infarction? / Troponin
26) Why would high-sensitivity C-reactive protein (CRP) be an indicator of a potential myocardial infarction? / It is an acute phase reactant plasma protein that rises in response to inflammation and the atherosclerotic process.
27) An ideal cardiac marker should be elevated in the circulation for how long following a cardiac event? / At least several days
28) A 55-year-old man is taken to a hospital emergency department by helicopter following a rural automobile accident that occurred approximately 3 hours ago. The man, who is having difficulty speaking to the EMTs, is clutching his chest. Upon the man’s arrival, the emergency room physician orders a cardiac marker panel that includes serum CK, CK-2 (CK-MB), troponin, and myoglobin. The CK-2 value was less than 2% of total CK, which was slightly increased; troponin was normal; and the myoglobin was increased 3 times the upper limit of normal. The physician has asked the laboratory to explain the findings. What represents the lab’s explanation? / Trauma caused by the accident with possible crush injury to the chest caused elevated myoglobin with normal troponin and CK-MB.
29) What cardiac markers is elevated for the longest period of time after a myocardial infarction? / Troponins
30) What is considered to be the most specific marker for adverse ventricular remodeling following an acute myocardial infarction? / Brain natriuretic peptide (BNP)
31) In regard to cardiac anatomy, the myocardium: / contains bundles of striated muscle fibers.
32) What specimen types and collection methods is best for laboratory assessment of brain natriuretic peptide (BNP) in the evaluation of congestive heart failure? / EDTA-anticoagulated whole blood or plasma in plastic blood collection tubes only
33) Laboratory measurements for brain natriuretic peptide (BNP) be reported in: / nanograms/liter.
34) A cardiac marker that increases progressively with increasing severity of disease and is not increased (or decreased) in conditions that mimic congestive heart failure is: / B-type natriuretic peptide.
35) The most common laboratory method used to assess brain natriuretic peptides is: / immunoassay.
36) What troponins appears as uncomplexed or free following myocardial injury? / Cardiac troponin I
37) In a point-of-care (POC) test for a cardiac biomarker used in the evaluation of an individual with possible acute coronary syndrome, what is a Laboratory Medicine Practice guideline of the National Academy of Clinical Biochemistry (NACB)? / POC assays should provide quantitative results.
38) Chest pain that is associated with a decrease in oxygen supply to the heart muscle but that exhibits no cellular necrosis based on cardiac troponin value and is considered a less severe event is referred to as: / angina.
39) In the process of atherosclerotic plaque formation, what is the typical precipitating event? / Damage to the endothelium of cardiac blood vessels
40) The protein in cardiac muscle fibers that regulates contraction is: / troponin.
41) Regarding assessment of congestive heart failure, NT-proBNP can be measured. This protein is: / the N-terminal fragment of pro-BNP.
42) In your clinical chemistry laboratory, you use an immunoassay to detect blood levels of NT-proBNP. You receive a filled green-top anticoagulant-containing plastic blood collection tube with a request for NT-proBNP. What is your next step? / Proceed, because this tube contains heparin and provides plasma after centrifugation, which is acceptable for the NT-proBNP assay.
43) What are the laboratory results for CK-MB and cardiac troponin in the following conditions: muscular dystrophy, polymyositis, and extreme physical activity? / CK-MB elevated, troponin normal
44) A 36-year-old individual visits her physician with a complaint of nausea, loss of appetite, weakness, and an inability to concentrate. Laboratory results indicate increased serum urea and creatinine, increased potassium, reduced glomerular filtration rate (GFR), low blood pH, anemia (low red blood cell count), and hypocalcemia. What is the likely diagnosis? / Uremia
45) The portion of a nephron considered the most metabolically active and that is involved in the reabsorption of 60% to 80% of the glomerular filtrate and that secretes 90% of hydrogen ion excreted by the kidney is the: / proximal tubule.
46) A patient with elevated serum nitrogen compounds, markedly reduced GFR, increased serum sodium and potassium, and metabolic acidosis is diagnosed with acute kidney injury (AKI). What is a likely cause? / Decreased cardiac output
47) What laboratory results would point to a diagnosis of acute nephritic syndrome in an individual who exhibits hypertension and edema? / Hematuria, sodium retention, decreased GFR, proteinuria
48) The functional unit of the kidney is the: / nephron.
49) If a physician requests a creatinine clearance on an individual, what is the physician attempting to determine? / Glomerular filtration rate (GFR)
50) What components of the renal system is most important for regulation of plasma electrolytes and acid-base balance? / Distal convoluted tubule
51) In homeostatic regulation of plasma acid-base concentrations, sodium is both actively and passively exchanged in the tubules for what ions? / Hydrogen
52) What statements regarding creatinine is correct? / Normal plasma creatinine does not always indicate normal kidney function.
53) Secretion of renin and aldosterone is induced by low blood pressure and volume. Renin is synthesized in the _____ and aldosterone is made in the _____. / kidney; adrenal gland
54) Secretion of renin and aldosterone is induced by low blood pressure and volume. What other hormone would be released in the event of low blood pressure and volume? / Antidiuretic hormone
55) A 45-year-old man visits his physician with complaints of insatiable thirst, sudden onset of fatigue, polydipsia, and polyuria. Laboratory results indicate a normal fasting blood sugar. Serum sodium was slightly elevated. Urine was clear and had low specific gravity (hypotonic). The most likely cause of these symptoms and laboratory results would be: / diabetes insipidus.
56) Upon microscopic examination, an individual’s urine shows many bacteria, white blood cells, and cellular casts composed of polymorphonuclear leukocytes. It is likely that this individual has: / pyelonephritis.
57) If an individual has a normal GFR and a hyperchloremic normal anion gap metabolic acidosis with a freshly voided early morning urine specimen which has a pH of 6.5, what is the likely diagnosis? / There is likely the onset of distal renal tubular acidosis (RTA).
58) Damage to the glomerulus would be suspected when the urine sediment contains: / red blood cell casts.
59) Why is bone disease a consequence of chronic kidney disease (CKD)? / When glomerular filtration declines, vitamin D activation decreases resulting in reduced calcium, which further leads to resorption of calcium from bone.
60) You have been asked what laboratory tests should be requested to assess the electrolyte balance regulatory function of an individual’s kidneys. What is your reply? / Serum sodium and potassium, and arterial blood pH
61) The major artery that expands into the capillary bed that forms the glomerulus is the: / renal artery.
62) The most common glomerular disease worldwide is: / IgA nephropathy.
63) A 46-year-old patient visits her physician with a complaint of chest pain, blood in her urine, and oliguria. She states that these symptoms have gotten worse over the past 2 to 3 months. Urine and blood samples are collected. Urine GFR is calculated to be 40 mL/min/1.73 m2 and hemoglobin is 8 g/dL. Urine protein was elevated, with the presence of red blood cell casts. Upon review of her health history, it was noted that she was a cigarette smoker with hypertension. The most likely diagnosis in this case would be: / chronic kidney disease (CKD).
64) In an individual with chronic kidney disease, what might be the predominant cause of the low hemoglobin value and anemia? / Decreased erythropoietin synthesis
65) An individual presents to his physician with generalized weakness and fatigue. Blood is collected and an elevated WBC count with lymphocytosis is noted. Serum protein is moderately decreased, but the urine reagent dipstick does not indicate proteinuria. Upon confirmatory testing with a precipitation test, the urine protein is 4+. Based on other symptoms, the physician suspects multiple myeloma. What might be the cause of the discrepancy in urine protein values? / Reagent dipsticks respond mostly to urine albumin and not to other proteins.