MLT 130 - Clinical Chemistry - Unit 1 Exam

Describe how to perform a 2-hour postprandial glucose.

- Patient drinks 75 mg glucose drink and glucose is drawn 2 hours later. - In a non-diabetic patent, glucose should have returned to a normal range. - A 2-hour postprandial glucose over 200mg/dl is indicative of diabetes mellitus

List 2 functions of lipids.

- Source of energy - Store excess calories

Name a syndrome that can occur in children after a viral illness treated with aspirin.

Reye's Syndrome

Why is it important that plasma be separated from the RBC within one hour in order for the plasma specimen for glucose testing to be accurate?

Separating them will prevent cellular use of glucose (glycolysis). The red cells will metabolize the glucose for energy (ATP) via glycolysis, thus we get a false decreased glucose result.

Describe HDL.

Take excess cholesterol to the liver

Calculate the LDL of this patient using the Friedewald calculation: Total cholesterol: 250 mg/dl HDL: 50 mg/dl Triglycerides: 160 mg/dl Is the LDL normal, decreased, increased? Formula: LDL = [total cholesterol] - [HDL + (triglycerides/5)]

· 168 mg/dl (Increased)

Distinguish between pre- renal, renal, and post renal causes of an elevated BUN.

· Pre-Renal: Occurs before the kidney due to reduced blood flow. Can cause dehydration, congestive heart failure, and shock. · Renal: Decreased renal function · Post-Renal: Obstruction of urine flow (kidney stones)

Describe the appearance of a patient's serum or plasma with increased triglycerides.

· clear, less than 200 mg/dl · hazy, 200-300 mg/dl · opaque, milky >600 mg/dl

Hormone produced by the adrenal medulla, inhibits insulin secretion, and raises plasma glucose is ______?

Epinephrine

Ketones are the metabolic products of ______?

Fat

Hormone produced by alpha cells of islets of Langerhans and raises plasma glucose is ______?

Glucagon

Formation of glucose from noncarbohydrate sources is called ______?

Gluconeogenesis

Monosaccharide sugars include? (3)

Glucose, Fructose, Galactose

Polysaccharide sugars include? (1)

Glycogen (energy storage for animals)

The conversion of glucose into glycogen for storage is called ______?

Glycogenesis

The breakdown of glycogen to form glucose is called ______?

Glycogenolysis

The conversion of glucose into lactate or pyruvate is called ______?

Glycolysis

Name conditions associated with hyperuricemia.

Gout, renal disease, leukemia patients or cancer patient on radiation/chemo (increased cell turnover) or a condition called Lesch-Nyhan.

Name the type of tube top color and anticoagulant it contains to prevent what happens in the question above.

Grey top tube (sodium fluoride)

Blood ammonia levels are usually measured in order to evaluate:

Hepatic Coma

Name the most accurate (the reference method) for glucose testing.

Hexokinase

List conditions associated with secondary hypercholesterolemia.

Hypothyroidism, DM, nephrotic syndrome, obstruction of bile duct.

Galactosemia is an inborn error of metabolism that is associated with _______?

an Enzyme Defect

Regarding whole blood vs. plasma glucose levels, which choice below is TRUE? a. Whole blood result is 15% higher b. Whole blood result is 15% lower c. Plasma result is 15% lower d. The difference between results should be negligible

b. Whole blood result is 15% lower

Which of the following lipid results would be expected to be falsely elevated on a serum specimen from a non-fasting patient? a. cholesterol b. triglyceride c. HDL d. LDL

b. triglycerides

Which statement below is true of the Hgb A1C test? a. results would not be affected in patients with a hemolytic anemia b. the preferred specimen is citrated whole blood c. levels do not need to be performed on a fasting specimen d. an increased level alone is diagnostic of diabetes mellitus

c. levels do not need to be performed on a fasting specimen

Uric acid is derived from:

catabolism of purines

Urea is produced from:

the catabolism of protein and amino acids

Disaccharide sugars include? (3)

Maltose, Lactose, Sucrose

What is Tangier's disease?

Mechanism unknown. Is due to familial absence of HDL.

Creatinine is a waste product from ______?

Muscle Metabolism

Are lipids water soluble?

No

Will creatinine levels be the same for men and women? Why?

No, because men typically have higher muscle mass than women

Describe gout.

Painful uric acid (monosodium urate) crystals form in joints. More common in males than females. Usually treat gout with medication allopurinol.

Describe how to perform a 3-hour OGTT.

Patient fasts for 10-16 hours. Perform in the morning. After patient finishes 75 mg glucose drink, draw glucose levels at the following intervals: ½ hour, 1 hour, 2 hours, and 3 hours.

A lipemic specimen collected from an adult after a 12 hour fast was assayed for total cholesterol, triglycerides, and HDL cholesterol using a direct method. The results were as follows: - Total cholesterol: 220 mg/dl - HDL cholesterol: 40 mg/dl - Triglyceride: 450 mg/dl The physician requests an LDL cholesterol after receiving the results. How should the LDL cholesterol be determined?

Perform a direct LDL assay

Plant starches are classified as:

Polysaccharides

Urea is the major waste product from ______ catabolism.

Protein

All of the following laboratory tests are used to determine kidney function EXCEPT? a. creatinine b. BUN c. microalbumin d. Hgb A1C

d. Hgb A1C

Describe the preferred specimens and testing criteria for an ammonia level.

Venous blood, EDTA or Heparin, obtained without trauma, on ice immediately, centrifuged at 0-4°C, must test within 20 min of collection, no hemolysis of specimen

Ammonia is BEST categorized as being:

a waste product of amino acid and protein metabolism

Which of the following would be associated with a reduced risk of heart disease? a. Apolipoprotein A-1 b. Apolipoprotein B-100 c. Lipoprotein (a) d. both b and c

a. Apolipoprotein A-1

Which of the following conditions is associated with hypoglycemia? a. Von Gierke disease b. hyperthyroidism c. increased growth hormone d. gestational diabetes

a. Von Gierke disease

Breakdown of glycogen to form glucose is called:

glycogenolysis

Which test is used to assess the average plasma glucose level that an individual maintained over a 10 to 12 week period?

glycosylated hemoglobin (Hgb A1C)

A positive test for microalbuminuria on a diabetic patient would indicate that the patient could have:

nephropathy (renal disease)

State the formula for creatinine clearance.

(U x V) / (B x T) U=Urine creatinine V=volume of the 24 hr urine in mL B=blood creatinine T= time in minutes (1440 min in 24 hr)

Name the test methodology most commonly used to measure creatinine levels. What is the primary reagent used?

- Jaffe Reaction - Picric Acid

The sodium nitroprusside test is positive for ______ and appears ______?

- Ketones - Purple

Excess carbohydrates are stored in the ______ in the form of ______?

- Liver - Glycogen

List normal ranges for plasma or serum creatinine.

- Male: 0.9-1.2 - Female: 0.6-1.1

Define Unsaturated Fatty Acids

- Monounsaturated fatty acid contains one double bond - Polyunsaturated fatty acid contains >1 double bond

The major protein found in HDL is:

Apo A-1

What is the amount of time a patient should fast for a lipid panel?

10-14 hours

Blood samples for most tests for lipids are drawn from a patient after:

12 hour fast

Calculate the concentration of urea corresponding to a urea nitrogen result of 27 mg/dl: Formula: BUN x 2.14 = Urea

58 mg urea/L

What is the normal range for plasma glucose?

70-99 mg/dL

A 2-hour post-prandial blood glucose sample is a blood sample taken 2 hours after a:

75 mg glucose drink

Explain what causes a patient to have an elevated ammonia level.

Advanced Liver Disease · Causes of advanced liver disease: acute viral hepatitis, Reye's syndrome, chronic hepatitis, drug, alcohol

Define Saturated Fatty Acids

All C bound to a H, no double bonds between carbons

Uric acid is a waste product from ______ catabolism.

Ammonia

Which unsaturated steroid alcohol is important as a precursor for hormone production:

Cholesterol

List a method of measurement for cholesterol?

Cholesterol oxidase, Lipoprotein Panel

The BUN test is not as good an indicator of renal clearance as creatinine because?

BUN can be influenced by factors such as diet and dehydration when creatinine isn't.

State formula used to calculate urea from BUN.

BUN x 2.14 = Urea

Name the lipoprotein that will form a creamy layer on top of plasma or serum.

Chylomicrons

What 3 elements do all carbohydrates contain?

Carbon, Hydrogen, Oxygen

Describe VLDL.

Carry triglycerides from liver to cell (tissues)

Which lipid is not an energy source?

Cholesterol

Why is creatinine the specimen of choice to measure renal clearance?

Creatinine is removed from the body by the kidneys, therefor creatinine is used in renal clearance to ensure that the kidneys are functioning properly

Describe LDL.

Deliver cholesterol to peripheral cells

Most glucose in the human body is in the _____form.

Dextro

The metabolic pathway that is anaerobic and produces 2 ATP is ______?

Embden Meyerhof Pathway (glycolysis).

Hormone produced by beta cells of islets of Langerhans and lowers plasma glucose is ______?

Insulin

Why perform urine microalbumin testing?

It is used to detect renal disease early

The reference analytic method for cholesterol is:

Liebermann Burchard

What are the 2 essential fatty acids?

Linoleic and Linolenic Acid

Impaired glucose metabolism often leads to increased metabolism of ______?

Lipids

Ketosis is a term associated with excessive degradation of ______?

Lipids

Which Exogenous (Dietary) lipid does chylomicrons deliver to the liver and peripheral cells?

Triglycerides

Which lipid is transported in the plasma by chylomicrons?

Triglycerides

Type of diabetes that is adult onset is ______?

Type 2 Diabetes Mellitus

A serum is observed to be milky. This is due to an elevated level of ______?

VLDL