Immunodiagnostics

Question 1

Why are diagnostic tests important?

Answer 1

1. Confirm/Excludes diagnosis
2. Determines treatments
3. Epidemiological surveillance
4. Prevention, control + eradication
5. Identification of pathogens

Question 2

Phases of testing

Answer 2

1. Pre Analytical- test selection, sampling, storage, transportation
2. Analytical- Handling and analysis
3. Post Analytical- report results, interpret

Question 3

Test selection

Answer 3

Determined by:

• Type of pathogen
• Type of sample
• Test characteristics
• Phase of disease
• Availability
• Cost

Question 4

Considering samples

Answer 4

Type of test, pathogen, and phase of disease

Question 5

Sensitivity

Answer 5

Measures a test to identify the positive (sick) individual

True positives- patients with the disease your looking for

Question 6

Specificity

Answer 6

Measures a test to identify negative idividuals

True negatives- Patient does not have the pathogen your looking for

Question 7

Positive Predictive Value

Answer 7

Probability of a positive test being a true positive

Question 8

Negative Predictive Value

Answer 8

Probability of a negative test being a true negative

Question 9

Prevalence

Answer 9

IMPT for predictive values (Specificity + Sensitivity)

Question 10

Serology

Answer 10

Study of antigen-antibody interactions in vitro

Infectious diseases, hormones, cancer, autoimmunity

Question 11

Direct Serology

Answer 11

Presence of antigen in sample

Positive result= infection

Question 12

Indirect Serology

Answer 12

Presence of antibodies in sample

Positive result= exposure

Question 13

Titer

Answer 13

Concentration of antibodies/ antigens

Coorlates w highest dilution at which antibodies/antigens are still detectable

Question 14

ELISA

Answer 14

Enzyme labeled antibodies or antigens to to detect or measure conc. of an analyte