Exam #2: Infectious Disease

Question 1

What type of organism does KOH Prep evaluate?

Answer 1

Yeast

Question 2

What type of diagnostic test dissolves all but fungi and elastin?

Answer 2

KOH Prep

Question 3

What condition does Tzanck Prep evaluate for, and what is seen if +?

Answer 3

Herpes virus

- Multinucleated giant cells = HSV

Question 4

What specific type of organism does India Ink evaluate?

Answer 4

Cryptococci in CSF

Question 5

What condition does Dark Field Microscopy evaluate for?

Answer 5

Syphilis

Question 6

What three diagnostic tests can be used to evaluate for Syphilis?

Answer 6

• Dark Field Microscopy
• Venereal Disease Research Laboratory (VDRL) via CSF
• Rapid Plasma Reagin (RPR) via serum

Question 7

What three diagnostic tests can be used to detect antibodies in serum?

Answer 7

• Latex Agglutination Assay
• Enzyme-Linked Immunoassay (ELISA)
• Indirect Immunofluorescence Assay (IFA)

Question 8

What two diagnostic tests can be used to detect bacterial/viral DNA or RNA sequences?

Answer 8

• Nucleic Acid Amplification Test (NAAT)

- Polymerase Chain Reaction (PCR)

Question 9

Why would NAAT or PCR be preferred over ELISA (3)?

Answer 9

• Faster
• More accurate
• More sensitive

Question 10

What condition does • Acid Fast Bacilli (AFB) stain evaluate for?

Answer 10

TB specific

- Most sensitive/specific for Mycobacterium

Question 11

What is Minimum Inhibitory Concentration (MIC)?

Answer 11

Lowest conc. of antibiotic necessary to inhibit visible growth

Question 12

When ordering blood cultures, what is the proper technique?

Answer 12

Collect 2 different specimens from 2 different sites

- BEFORE abx

Question 13

Why would a redraw of blood cultures be indicated, and when (think specific organism)?

Answer 13

Within 48 hours if due to S. aureus (R/O MRSA)