Clinical Chemistry II Quiz 1

What is the normality of a solution containing 4.5 grams of BaCl 2 in 400 mL? (gmw = 208) 0.11 0.25 1.10 0.50

0.11

Board Review Question: What is the molarity of a solution that contains 18.7 g of KCl (MW=74.5) in 500 mL of water? 0.1 0.5 1.0 5.0

0.5

A patient's creatinine is outside the linear range of the analyzer; 10 µL of serum is added to 90.0 µL of diluent and the diluted sample is reanalyzed. The creatinine value of the diluted sample is 1.0 mg/dL. Which of the following creatinine values is correct? 1.0 mg/dL 10.0 mg/dL 20.0 mg/dL 100 mg/dL

10.0 mg/dL

Convert 40°C to °F. 60°F 90°F 100°F 104 °F

104 °F

How many millimoles of NaCl are contained in 300 mL of a 4M solution? (gmw = 58.5) 234 120 1200 70

1200

Blood glucose is present at above the linearity of the assay for a diabetic in ketoacidosis. The sample is diluted with one part sample and 2 parts diluent. The diluted result is 450 mg/dL. What is the correct glucose concentration? 225 mg/dL 450 mg/dL 900 mg/dL 1350 mg/dL

1350 mg/dL

How many grams of hydrated MgSO 4 ⋅ 5 H 20 (M.W.: MgSO 4 = 119, H 20 = 18) are required to make a 10% solution of MgS0 4? 20.9 g/dL 11.9 g/dL 17.6 g/dL 5.7 g/dL

17.6 g/dL

How many grams of hydrated MgSO 4 ⋅ 5 H 20 (M.W.: MgSO 4 = 119, H 20 = 18) are required to make a 10% solution of MgS0 4? 20.9 g/dL 17.6 g/dL 11.9 g/dL 5.7 g/dL

17.6 g/dL

Board Review: 4 mL of water are added to 1 mL of serum. This represents which of the following serum dilutions? 1:3 1:4 1:6 1:5

1:5

Board Review Question: How many milliliters of 30% bovine albumin are needed to make 6 mL of a 10% albumin solution 1 2 3 4

2

Convert 200 picograms to grams. 2.0 x 10-10 grams 2.0 x 10-8 grams 20.0 grams 200 grams

2.0 x 10 - 8 grams

The molarity of calcium is 40 mg per millimole. Convert 10 mg/dL of calcium to mmol/L of calcium. 10 mmol/L 20 mmol/L 5 mmol/L 2.5 mmol/L

2.5 mmol/L

Board Review Question: A 600 mg/dL glucose solution is diluted 1/30. The concentration of the final solution in mg/dL is: 2 20 180 1800

20

If 10 mL of sample is added to 190 mL of diluent, what is the dilution factor? 10 19 20 25

20

Board Review: The volume of 25% stock sulfosalicylic acid needed to prepare 100 mL of 5% working solution is: 20 mL 50 mL 1.25 mL 5 mL

20 mL

A patient sample for uric acid gave an absorbance reading of 0.4, and the 50 mg/dL standard gave an absorbance reading of 0.1. What is the concentration of uric acid in the patient's sample in grams per deciliter? 12.5 0.2 200 125

200

Board Review Question: How many milliliters of a 3% solution can be made if 6 g of solute are available? 100 mL 200 mL 400 mL 600 mL

200 mL

A 1 to 4 dilution must be prepared to make a total volume of 100.0 µL. How much serum must be used? 0.025 µL 0.25 µL 2.5 µL 25 µL

25 µL

Board Review: An automated CK assay gives a reading that is above the limits of linearity. A dilution of the serum sample is made by adding 1 mL of serum to 9 mL of water. The instrument now reads 350 U/L. The correct report on the undiluted serum should be: 3,850 U/L 3,150 U/L 2,850 U/L 3,500 U/L

3,850 U/L

If a thermometer reads 39°F, what is the equivalent degree Celsius? 0.39°C 3.9°C 39°C 40°C

3.9°C

Board Review Question: How many grams of sodium chloride are needed to prepare 1L of 0.9% normal saline? 0.9 1.8 9.0 18.0

9.0

Board Review: A mean value of 100 and a standard deviation of 1.8 mg/dL were obtained from a set of glucose measurements on a control solution. The 95% confidence interval in mg/dL would be: 94.6 - 105.4 96.4 - 103.6 98.2 - 101.8 97.3 - 102.7

96.4 - 103.6

Which of the following classes of glassware, including pipets, is manufactured and calibrated to deliver the most accurate volume of liquid? A B AA C

A

Board Review Question: A one molal solution is equivalent to: a solute containing one mole of solute per kg of solvent 1000 mL of solution containing one mole of solute a solution containing one gram-equivalent weight of solute in one liter of solution a 1-L solution containing 2 moles of solute

a solute containing one mole of solute per kg of solvent

Select the bases that are present both in DNA and RNA adenine cytosine guanine thymine uracil

adenine cytosine guanine

Which type of centrifuge is this? angle head axial horizontal head ultracentrifuge

angle head

When centrifuging samples, improper centrifugation speed can release cellular materials into serum or plasma. can increase the turnaround time for centrifugation. will have no effect on urine sediments. All of these are correct.

can release cellular materials into serum or plasma.

CLRW can be produced using: distillation distillation with additional filters reverse osmosis distillation or reverse osmosis, with additional filters

distillation or reverse osmosis, with additional filters

Board Review Question: The nanometer is used as a measure of absorbance % transmittance intensity of radiant energy wavelength of radiant energy

intensity of radiant energy

Board Review: The statistical term for the average value is the: mean median mode coefficient of variation

mean

Board Review: The middle value of a data set is statistically known as the: mode mean median standard deviation

median

Board Review: The most frequent value in a collection of data is statistically known as: mean mode standard deviation median

mode

Board Review: In performing a spinal fluid protein determination, the specimen is diluted 1 part spinal fluid to 3 parts saline to obtaina result low enough to measure. To calculate the protein concentration, the result must be: divided by 3 multiplied by 3 divided by 4 multiplied by 4

multiplied by 4

Board Review Question: Which of the following is the formula for calculating the molarity of a solution? number of moles of solute/ L of solution number of moles of solute x 100 1 GEW of solute x 10 1 GEW of solute / L of solution

number of moles of solute/ L of solution

Which of the following is most insoluble in water? DNA Triglycerides Albumin Sucrose

Triglycerides

Board Review: Which of the following is the formula for arithmetic mean? sum of values/number of values number of values/sum of values square root of the sum of values sum of values x number of values

sum of values/number of values

A serum creatine kinase (CK) is diluted 1/200 with a result of 50 U/L. What is the patients' actual CK result? 50 U/L 200 U/L 1000 U/L 10,000 U/L

10,000 U/L

One nanogram is equivalent to how many grams? 10-15 10-9 10-6 10-12

10-9

Board Review: Which of the following is the formula for coefficient of variation? (standard deviation x 100)/standard error (standard deviation x 100)/mean (mean x 100)/standard deviation (variance x 100)/mean

(standard deviation x 100)/mean

Board Review: The following 5 sodium control values in unit (mEq/L) were obtained: 140, 135, 138, 140, 142 Calculate the coefficient of variation. 2.7% 5.6% 6.1% 1.9%

1.9%

Board Review Question: If 0.5 mL of a 1/300 dilution contains 1 antigenic unit, 2 antigenic units would be contained in 0.5 mL of a dilution of: 1/150 1/450 1/500 1/600

1/150

Board Review: The acceptable limit of error in the chemistry laboratory is 2 standard deviations. If you run the normal control 100 times, how many of the values would be out of the control range due to random error? 1 10 5 20

10

How many milliliters of concentrated sulfuric acid (H 2S0 4), G.M.W. = 98 grams, specific gravity = 1.500, purity = 80%, are needed to make 400 mL of a 2N solution? 65.3 26.1 32.7 52.3

32.7

Board Review Question: A solution contains 20 g of solute dissolved in 0.5 L of water. What is the percentage of this solution? 2% 4% 6% 8%

4%

How many milliliters of 0.5N NaOH are required to make 100 milliliters of 0.2N NaOH? A. 40 B. 4 C. 250 D. 25

40

What type of specimen provides the fastest turnaround times for blood gas analysis? A. Urine B. Plasma C. Whole blood D. Serum

A. Urine

What is the normality of a solution containing 4.5 grams of BaCl 2 in 400 mL? (gmw = 208) A. 0.11 B. 0.25 C. 0.50 D. 1.10

A. 0.11

Which chemical group does the compound CH 3CH 2OH belong to? Alcohol Ketone Ester Amine

Alcohol

Which of the following statements is NOT TRUE of capillary blood? A. May be used in place of arterial blood when blood gases are done on an infant B. Is more similar to venous than arterial blood for concentrations of analytes C. Most chemistry analytes are similar to venous blood values except glucose D. May be collected from the fingertip of an adult or heel of an infant

B. Is more similar to venous than arterial blood for concentrations of analytes

What are the optimal conditions for specimen transport, handling, and storage of specimens for clinical chemistry testing? A. Specimen transported to lab within 2 hours after collection, stored at room temperature, and centrifuged within 4 hours. B. Specimen transported to lab immediately, permitted to clot, serum separated and tested as soon as possible. C. Specimen brought to lab immediately, spun down, and serum left to stand on clot until tested. D. None of these represent optimal conditions.

B. Specimen transported to lab immediately, permitted to clot, serum separated and tested as soon as possible.

A STAT glucose specimen was drawn and sent to the laboratory. The specimen was retrieved from the pneumatic tube system and centrifuged immediately. After the serum specimen was then loaded onto the analyzer, a sample aspiration error occurred. What specimen collection and handling error most likely caused the error? A. A plasma specimen should have been collected instead of serum. B. The specimen was not completely clotted prior to centrifugation. C. A temperature-controlled fixed angle centrifuge should have been used. D. The specimen should have been hand-carried to the laboratory.

B. The specimen was not completely clotted prior to centrifugation.

How is 10 mg/dL of calcium reported in mmol/L? (gmw = 40) A. 10 B. 2.5 C. 5.0 D. 25

B. 2.5

20 mg/dL is equivalent to _______ parts per million (ppm). A. 2 B. 200 C. 2000 D. 20

B. 200

How many milliliters of concentrated sulfuric acid (H 2S0 4), G.M.W. = 98 grams, specific gravity = 1.500, purity = 80%, are needed to make 400 mL of a 2N solution? A. 65.3 B. 32.7 C. 52.3 D. 26.1

B. 32.7

Diurnal variation is a term that refers to which of the following? A. Collection of 24-hour urine specimens B. Time of day specimen collection occurs C. Whether a patient is resting or exercising D. Whether a patient is fasting or nonfasting

B. Time of day specimen collection occurs

Ideally, the best type of centrifuge that separates blood cells and plasma for analysis in the clinical laboratory is: A. A non-temperature-controlled centrifuge with fixed buckets that hold 5-10 mL blood tubes B. A non-temperature-controlled centrifuge with fixed buckets that only hold 1 mL blood tubes C. A temperature-controlled centrifuge with spinning buckets that holds 5-10 mL blood tubes D. A temperature-controlled centrifuge with fixed buckets and an angled rotor

C. A temperature-controlled centrifuge with spinning buckets that holds 5-10 mL blood tubes

Which of the following centrifuges minimizes pre-analytical errors associated with the analysis of ammonia specimens? A. A non-temperature-controlled centrifuge with swinging buckets B. A non-temperature-controlled centrifuge with fixed buckets C. A temperature-controlled centrifuge with swinging buckets D. A temperature-controlled centrifuge with fixed buckets and an angled rotor

C. A temperature-controlled centrifuge with swinging buckets

Which federal organization governs the operation of clinical laboratories? Centers for Medicare and Medicaid Services College of American Pathologists The Joint Commission Centers for Disease Control and Prevention

Centers for Medicare and Medicaid Services

3 mg/dL is equivalent to how many grams per liter? A. 0.003 B. 0.3 C. 3 D. 0.03

D. 0.03

What is the molarity (M) of a 4% solution of sodium hydroxide (NaOH)? M.W: Na = 23, O = 16, H = 1. A. 0.1M B. 2.5M C. 0.25M D. 1.0M

D. 1.0M

Convert 10 mg/dL of calcium to mmol/L. (mw = 40) A. 10 B. 25 C. 5.0 D. 2.5

D. 2.5

Which of the following devices is used to calibrate laboratory thermometers? Barometer Gallium melting point cell Titanium freezing point cell Platinum cathode voltmeter

Gallium melting point cell

A to deliver or TD pipets are designed to: Allow the user to remove a portion of the sample in the tip for better accuracy. Be vigorously tapped against the test tube after all the liquid is removed. Drain by gravity. Be refilled or rinsed out with the appropriate solvent after the initial liquid has been drained from the pipet.

Drain by gravity.

Reverse osmosis (RO) is described as a process: In which water is forced through a semipermeable membrane that acts as a molecular filter. Used to purify liquid chemicals. In which water forced through a carbon filter eliminates organic solvents. In which salt in water moves through filter paper.

In which water is forced through a semipermeable membrane that acts as a molecular filter.

The unit of resistivity is: Amperes. Volts. Coulombs. M Ω cm

M Ω cm

Which of the following should not be storied in borosilicate glass because it will etch the inside surface of the glass container? Saline Strong bases (caustics) Clinical laboratory reagent water Weak acids

Strong bases (caustics)

Activated carbon filters remove: Ions from water. Organic compounds from water. Acids and bases from water. Large particulates from water.

Organic compounds from water.

A 0.22-micron filter will remove: Particles with a diameter of 0.01 microns. Particles with a diameter of 0.01 nanometer. Particles with a diameter of 2.2 microns. Only sodium chloride crystals.

Particles with a diameter of 2.2 microns.

Board Review Question: Which of the following is the formula for calculating a percent (w/v) solution? grams of solute/volume of solvent x 100 grams of solute x volume of solvent x 100 volume of solvent/grams of solute x 100 (grams of solute x volume of solvent)/100

grams of solute/volume of solvent x 100

Board Review: When the exact concentration of the solute of a solution is known and is used to evaluate the concentration of an unknown solution, the known solution is: normal baseline standard control

standard