Week 2 Lab: Screening Test for Phagocytic Engulfment

Question 1

True or False: No special preparation of the patient is required before specimen collection.

Answer 1

True

Question 2

Blood should be drawn by an _____ technique.

Answer 2

aseptic

Question 3

Blood sample: A minimum of ______________ or ______________ are required.

Answer 3

• 2 mL of heparin blood (green-top evacuated tube)
• 15 to 20 heparinized capillary tubes

Question 4

After blood collection, the specimen should be _________.

Answer 4

centrifuged

Question 5

For the quality control, _________________ should be tested simultaneously.

Answer 5

a fresh, heparinized sample of blood from a healthy volunteer

Question 6

Materials for the experiment?

Answer 6

• Broth culture of Bacillus subtilis or Staphylococcus epidermidis
• Microscope slides
• Pasteur pipettes
• Rubber bulb
• Test tubes
• Wright’s stain

Question 7

What are the labels of the 2 test tubes?

Answer 7

Patient test tube and Control test tube

Question 8

Add ______ drops of the buffer coat from either blood sample to the respectively labeled tubes.

Answer 8

4 to 8 drops

Question 9

Add ______ drops of the bacterial broth culture to each tube.

Answer 9

2 to 3 drops

Question 10

Incubate both tubes at room temperature or _____ for _____.

Answer 10

37C; 30 minutes

Question 11

Place _____of the incubated specimen on a glass slide and prepare a smear.

Answer 11

1 drop

Question 12

Air dry the slides and stain with _________.

Answer 12

Wright’s stain

Question 13

Cover each smear generously with filtered Wright’s stain and allow the stain to remain on the slide for at least _________.

Answer 13

5 minutes

Question 14

Slowly add distilled water or buffer to the stain until the buffer begins to overflow the stain. Watch for the appearance of a _________.

Answer 14

metallic luster

Question 15

Gently _____ on the slide to mix the stain and buffer.

Answer 15

blow

Question 16

Allow the buffer to remain on the slide for at least _________.

Answer 16

5 minutes

Question 17

Gently wash the stain and buffer off the slide with ___________.

Answer 17

distilled water

Question 18

Air dry or carefully blot the slide between two sheets of ___________.

Answer 18

bibulous paper

Question 19

Interpretation of Results: Positive?

Answer 19

Demonstration of the engulfment of bacteria

Question 20

Interpretation of Results: Negative?

Answer 20

No engulfment of bacteria

Question 21

It is the process by which specialized cells engulf and destroy foreign particles such as microorganisms or damaged cells.

Answer 21

Phagocytosis

Question 22

___________ are the most important phagocytic cells.

Answer 22

Macrophages and neutrophils (PMNs)

Question 23

A mixture of bacteria and phagocytes is incubated and examined for the presence of engulfed bacteria. This simple procedure may be useful in supporting the diagnosis of ___________________ in conjunction with clinical signs and symptoms.

Answer 23

impaired neutrophilic function

Question 24

This procedure may produce ____________ if the blood specimen is not fresh or if a coagulase-positive Staphylococcus specimen is used.

Answer 24

false-negative results

Question 25

This procedure may produce false-negative results if _______________.

Answer 25

• the blood specimen is not fresh
• if a coagulase-positive Staphylococcus specimen is used

Question 26

In Addition, the bacteria must be ___________ for the test to be positive.

Answer 26

intracellular and not extracellular

Question 27

The failure of phagocytes to engulf bacteria can support the diagnosis of __________; however, these results must be used in conjunction with patient signs and symptoms.

Answer 27

neutrophilic dysfunction

Question 28

True or False: This is the simple screening procedure for engulfment. The presence of engulf bacteria does not demonstrate that the bacteria have been destroyed.

Answer 28

True