Lab Dx Of Ebv And Hiv

Front 1

If initial exposure to EBV occurs during adolescence or adulthood, what is the likelihood of getting mononucleosis?

Back 1

50%

Front 2

Reactivation of EBV occurs in what subset of patients?

Back 2

immunocompromised

Front 3

Can EBV be cultured using standard cell cultures?

Back 3

NO

Front 4

When do heteophile antibodies of infectious mononucleosis appear?

Back 4

within the first 3 weeks of infection, then taper off rapidly

Front 5

What is a likely result of testing for infectious mononucleosis heterophile antibodies during the first week of infection?

Back 5

negative result is likely

Front 6

How often does primary EBV infection fail to produce heterophile antibodies in adults? in children?

Back 6

adults: 10%

children/infants: 99%

Front 7

Monospot

Back 7

not specific for EBV, but associated with infectious mononucleosis

tests to see if heterophile antibodies present to agglutinate horse/sheep/bovine RBCs

Front 8

When is the Monospot test the least specific?

Back 8

during the first two weeks

week 1: 25% FN
week 2: 5-10% FN

Front 9

What percentage of children under the age of 2 have Ab to the Monospot test?

Back 9

<30%

Front 10

What percentage of children aged 2-4 have Ab to Monospot test?

Back 10

<75%

Front 11

What percentage of persons under age 12 have Ab to the Monospot test?

Back 11

<50%

Front 12

What percentage of persons >12 have Ab to the Monospot test?

Back 12

>70%

Front 13

What is included in a "typical" EBV serology panel?

Back 13

Viral Capsid Antigen IgG

Viral Capsid Antigen IgM

Epstein-Bar Nuclear Antigen IgG

Front 14

What is the EBV early antigen an indicator of?

Back 14

reactivation of the virus

Front 15

When do the EBV panel Ab specifically show up and how long are they in blood?

Back 15

VCA IgM: show up immediately but are missing after seroconversion to IgG and is an indicator of recent infection

VCA IgG: show up after seroconversion and are an indicator of past infection

EBNA: detectable after 6-8 weeks and is constantly present in infected individuals (5-10% won't develop this Ab)

Front 16

EBV Early Antigen Titers

Back 16

Typically, <1:10, but reactivated infections may present with titers of >1:40

Front 17

What stage of EBV infection is signified by the following:
VCA IgM: +
EBNA: -

Back 17

Primary infection.

Remember, even with VCA IgG positive or rising, this is still a primary infection if there is no EBNA

Front 18

What stage of EBV infection is signified by the following:
VCA IgG: +
VCA IgM: -
EBNA: +

Back 18

past infection

Front 19

What stage of EBV infection is signified by the following:
VCA IgG: +
VCA IgM: -
EBNA: +
Early Antigen: rising/high titer

Back 19

Reactivation

Front 20

HIV Genotype Testing

Back 20

actual HIV gene sequence of pts virus is analyzed and compared to known mutations which lead to drug resistance

Front 21

HIV Phenotype Testing

Back 21

Pt's virus is grown in presence of drugs to determine drug susceptibility

Front 22

HIV Virtual Phenotype

Back 22

Genotype is compared to database and phenotype predicted based on sequence

Front 23

HIV Western Blot

Back 23

Detects Ab to HIV, not the virus itself

Identifies which components of the virus the Ab reacts to

2 of 3 necessary for Western +: gp24, 41, 120/160 (gp24 is Gag protein; the rest are envelope proteins)

Front 24

gp24

Back 24

First band, sometimes only band, to show up in seroconversion, but eventually disappears in late stage disease

Front 25

Possible reasons for indeterminate result

Back 25

Seroconverter
Cross-reacting Ab
Unknown
Pediatric loss of maternal Ab

Front 26

HIV-1 RNA PCR

Viral Load

Back 26

Prognostic monitoring of response to therapy

Baseline established/monitored periodically and after any change in therapy

Undetectable levels of RNA does NOT mean there is no infection

Front 27

HIV-DNA PCR

Back 27

Used to clarify infections status (indeterminate Western, pediatric pt, prior to seroconversion)

Front 28

Rapid HIV Testing

Back 28

Positives MUST be followed up with WB or immunoflorescence assay

Lead agency must obtain a CLIA certificate of waiver

Front 29

Risk Factors for Seroconversion after Occupational Exposure

Back 29

Device visibly contaminated with blood

Needle placed directly in vein/artery

Source individual died soon after exposure or was recently infected (high VL)

Use of hollow-bore needle

Failure of taking ZDV prophylaxis