Deck 9: Principles of Serological Testing

Question 1

If there will be an unavoidable 4-hour delay before a serum sample can be tested,the sample should be:

A) kept at room temperature.
B) refrigerated between 2°C and 8°C.
C) frozen at -20°C.
D) discarded and a new sample collected when it can be tested immediately.

Answer 1

refrigerated between 2°C and 8°C.

Question 2

If complement interferes with test results,the serum sample should be:

A) treated with an anticoagulant.
B) frozen and thawed before testing.
C) heated to 56°C for 30 minutes.
D) centrifuged at 3,000 g for 30 minutes.

Answer 2

heated to 56°C for 30 minutes.

Question 3

A patient's serum must be added to a series of test tubes,but a different volume of serum must be added to each tube.If a single pipette is used,what kind is it?

A) Graduated
B) Volumetric
C) Analytic
D) Calibrated

Answer 3

Graduated

Question 4

What type of pipette must be blown out to deliver the exact volume of liquid?

A) Volumetric
B) Serological
C) Analytic
D) Multichannel

Question 5

The concentration of a solution is reduced by adding:

A) solute.
B) particles.
C) diluent.
D) osmoles.

Question 6

Serology is the study of:

A) white blood cells.
B) red blood cells.
C) platelets.
D) the liquid components of the blood, especially antibodies.

Question 7

If 0.9 mL of saline is added to 0.1 mL of serum,what does the 0.9 mL represent?

A) The final dilution
B) The diluent
C) The solute
D) The total solution

Question 8

A blood sample is processed,and the resulting serum is pink.This indicates:

A) a normal serum sample.
B) a hemolyzed serum sample, but hemolysis is common and can be ignored.
C) a hemolyzed serum sample, which may adversely affect testing.
D) definite evidence of bacterial contamination.

Question 9

On a serial dilution with the following tubes set up,1:2,1:4,1:8,1:16,1:32,and 1:64,there is no visible agglutination in the 1:64 tube.What is the titer of the antibody?

A) 32
B) 16
C) 64
D) Cannot be determined

Question 10

The probability that a person with a positive screening test actually has the disease screened for is called:

A) sensitivity.
B) specificity.
C) positive predictive value.
D) negative predictive value.

Question 11

A new assay is used to test 120 samples from patients with a clinically confirmed diagnosis of the relevant infection and 50 samples from healthy control subjects.The test results were positive for 90 of the infected patients and positive for 10 of the healthy controls.
Calculate the assay's specificity.

A)57%
B)75%
C)80%
D)90%

Question 12

A blowout pipette would be labeled:

A) TD.
B) TC.
C) ML.
D) SD.

Question 13

When 0.5 mL of serum is added to 1.5 mL of diluent,what dilution does this represent?

A) 1:3
B) 1:4
C) 1:5
D) 3:1

Question 14

To prepare 70 ml of a 10% solution of acetic acid,how much acetic acid is needed?

A) 0.7 mL
B) 7 mL
C) 10 mL
D) 1.4 mL

Question 15

Which series of dilutions would be best in order to make a 1:3000 dilution?

A) 1:10, 1:3, 1:10
B) 1:5, 1:6, 1:100
C) 1:3, 1:100, 1:100
D) 1:30, 1:10, 1:100

Question 16

If you want to make 4 mL of a 1:20 dilution,how much serum would be needed?

A) 0.2 mL
B) 2 mL
C) 0.5 mL
D) 1 mL

Question 17

A new assay is used to test 120 samples from patients with a clinically confirmed diagnosis of the relevant infection and 50 samples from healthy control subjects.The test results were positive for 90 of the infected patients and positive for 10 of the healthy controls.
What is the sensitivity of the assay?

A)57%
B)75%
C)80%
D)90%

Question 18

A new assay is used to test 120 samples from patients with a clinically confirmed diagnosis of the relevant infection and 50 samples from healthy control subjects.The test results were positive for 90 of the infected patients and positive for 10 of the healthy controls.
If the assay was used to test a different population consisting of 240 infected patients and 50 healthy controls,which assay parameter would increase?

A)Sensitivity
B)Specificity
C)Positive predictive value
D)Negative predictive value

Question 19

A new assay is used to test 120 samples from patients with a clinically confirmed diagnosis of the relevant infection and 50 samples from healthy control subjects.The test results were positive for 90 of the infected patients and positive for 10 of the healthy controls.
Calculate the positive predictive value of the assay.

A)57%
B)75%
C)80%
D)90%

Question 20

An antibody titer is defined as the reciprocal of the:

A) last serial dilution tube in which a positive reaction is still visible.
B) first serial dilution tube in which a negative reaction is achieved.
C) diluent divided by the solvent.

Question 21

How should a 1:50 dilution be made if the final volume needed is 10 mL?

A) 0.1 mL of serum and 9.9 mL of diluent
B) 0.2 mL of serum and 9.8 mL of diluent
C) 0.2 mL of serum and 10.0 mL of diluent
D) 0.5 mL of serum and 9.5 mL of diluent