7) IFA Flashcards

1
Q

main purposes of serological testing

A
  • monitor course of infection
  • detect past infection
  • assess immune status
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2
Q

IgM in a newborn indicates…

A

congenital infection
(not mom’s)

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3
Q

molecular assays for viral nucleic acids are especially valuable for infections of the…

A

CNS

small amts of organism

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4
Q

IFA uses —— to detect ———

A

fluorochrome-labelled conjugate

Ab in pt serum

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5
Q

most common fluorochrome

A

FITC

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6
Q

direct IFA

A

pt tissue on slide + conjugate Ab + fluorochrome

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7
Q

indirect IFA

A

substrate with Ag on slide + pt serum (Ab) + conjugate + fluorochrome

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8
Q

IFA is (more/less) sensitive than EIA

A

less

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9
Q

disadvantages of IFA

A
  • background fluorescence
  • nonspecific binding to substances in serum
  • fluorochromes sensitive to pH, light
  • reading must be done frequently to maintain competency
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10
Q

advantages of IFA

A
  • fairly sensitive
  • no hazardous materials
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11
Q

fluorescent method developed to overcome IFA’s problems, but requires expensive instrumentation

A

fluorescent polarization immunoassay (FPIA)

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12
Q

lamp in fluroescent microscope must emit…

A

proper wavelength to excite fluorochrome

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13
Q

exciter filter in fluroescent scope

A

removes wavelengths other than one needed

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14
Q

barrier/emission filter in fluorescent scope

A

screens out light other than that produced by fluorochrome

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15
Q

complications associated with EBV

A
  • Burkitt’s lymphoma
  • nasopharyngeal carcinoma
  • B-cell lymphomas
  • chronic fatigue syndrome (not proven)
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16
Q

EBV-EA indicates…

A

active infection

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17
Q

EBV-M indicates…

A

acute infection

disappears after 3 months

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18
Q

EBV-G indicates…

A

current or past infection

90% pop has it by adulthood

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19
Q

EBNA detectable in….

A

convalescent stage of EBV

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20
Q

rapid mono detects…

A

heterophile Ab

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21
Q

produced by 40% EBV pts by week 1, and 90% by week 4

A

heterophile Ab

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22
Q

heterophile Ab sensitivity low in…

A

children <12 yo

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23
Q

negative heterophile Ab reflex

A

EBV-M serology

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24
Q

autoAb that EBV can trigger

A
  • cold agg
  • RF
  • ANA
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25
Q

most of pop exposed by elderly years, majority are asymptomatic or have mono-like illness

A

CMV

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26
Q

CMV life-threatening for…

A

newborns
immcomp

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27
Q

most common congenital viral infection

A

CMV

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28
Q

50% newborns with CMV develop…

A

sequelae (visual impairments, hearing loss, mental retardation)

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29
Q

immcomp patients especially vulnerable to CMV

A

aids
transplant

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30
Q

CMV in immcomp pts can affect…

A

eyes
liver
lungs
GI
CNS

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31
Q

identifies risk for disseminated CMV

A

CMV-DNA by PCR

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32
Q

method of choice for CMV serology

A

EIA

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33
Q

utility of CMV-G

A

documenting past infection in organ or blood donors

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34
Q

utility of CMV-M

A

limited
false negative and positives

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35
Q

primary infection occurs as gingivostomatotitis in children

A

HSV-1

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36
Q

retreats to nerve ganglia as dormant infection (can be fatal)

A

HSV-1

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37
Q

bilateral genital lesions with fever, lymphadenopathy, dysuria

A

HSV-2

38
Q

utility of HSV-M

A

usually not tested for

39
Q

utility of HSV-G

A

remains detectable throughout life

look for significant rise in titer

40
Q

method of choice for detecting acute HSV infection

A

PCR for HSV nucleic acid

41
Q

VZV transmission

A
  • resp secretions or aerosols from skin lesions
  • mother to fetus
42
Q

VZV can cause congenital malformations in…

A

1st trimster

43
Q

> 95% of infections are in children

A

chickenpox

44
Q

reactivation of chickenpox virus

A

zoster/shingles

45
Q

utility of VZV-G

A

determine immune status of individual, especially pregnant women exposed during their pregnancy

46
Q

given to pregnant women for passive immunity to VZV, but must be within —– hrs of exposure

A

VZIG
96

47
Q

most accurate & sensitive method for detecting VZV infection

can be performed on CSF

A

VZV-DNA by PCR

48
Q

protozoan parasite that replicates inside macros

A

Toxoplasma gondii

49
Q

T. gondii transmission

A
  • ingestion of oocysts (contaminated soil, cat litter, undercooked beef or pork)
  • transfusion/transplant
  • mother to fetus
50
Q

T. gondii complications

A
  • can invade CNS and be lethal in immcomp
  • death to fetus almost always in 1st tri
  • hydrocephaly, blindness in 2nd tri
51
Q

methods of choice for T. gondii serology

A

enzyme or chemiluminescent immunoassay

PCR method of choice for CSF, tissues

52
Q

German measles

A

Rubella virus

53
Q

mainly seen in young unvaxxed immigrants

A

rubella

54
Q

can be subclinical or rash starting on face and spreading to extremities

A

rubella

55
Q

Rubella effects on fetus

A
  • miscarriage
  • Rubella syndrome (deafness, eye defects, cardiac defects, mental retardation, motor disabilities)
56
Q

method of choice for rubella Ab detection

A

ELISA

57
Q

RUB-G utility

A

persists for life and indicates immunity if titer high enough

58
Q

7 day measules

A

rubeola virus

59
Q

Koplik’s spots (red with gray in center) in mouth

maculopapular rash

A

Rubeola

60
Q

rare complication of rubeola

A

SSPE - subacute sclerosing panencephalitis

fatal degenerative disease of CNS

61
Q

effects of rubeola on fetus

A
  • miscarriage
  • preterm labor
  • low birth weight
62
Q

virus begins in nasopharynx and regional lymph nodes

moves to various tissue

A

mumps

63
Q

complications of mumps

A
  • meningitis
  • deafness
  • fetal death in 1st tri
64
Q

protects babies up to 6 months or older from mumps

A

mother’s Ab transferred through placenta

65
Q

because of vaccines, assays to detect measles & mumps IgG are performed mainly…

A

to determine immune status

66
Q

walking pneumonia

A

M. pneumoniae

67
Q

leading cause of URT infection worldwide

A

M. pneumoniae

68
Q

most widely used technique for M. pneumoniae

A

EIA

69
Q

causes anti-I cold agglutinins

A

M. pneumoniae
(about 50% pts)

70
Q

IgM can persist for considerable lengths of time, so not used to detect acute infection

A

L. pneumophila

71
Q

bullseye rash in —– of lyme patients

A

60-80%

72
Q

complications of lyme

A
  • dissemination to multiple organ systems
  • chronic stage including arthritis
73
Q

Lyme-G peaks…

A

6 months after onset, during arthritic sx

74
Q

IFA for lyme uses ——- as substrate

A

spirochete

75
Q

highly subjective and difficult to read, with beading fluorescence indicating false pos

A

IFA for lyme

76
Q

recommendation to dx lyme

A
  • screen with lyme-G by EIA
  • confirm with western blot
77
Q

gold standard for confirming rickettsial diseases

A

IFA

78
Q

rickettsial organisms/diseases

A
  • Bartonella quintana (bacillary angiomatosis)
  • Bartonella henselae (bacillary angiomatosis, cat scratch fever)
  • Coxiella burnetii (Q fever)
  • Rickettsia rickettsii (RMSF)
  • Rickettsia typhi (typhus)
  • Ehrlichiosis
  • Ehrlichia chaffeensis (HME)
  • Anaplasma phagocytophilum (HGE)
79
Q

recommended rickettsial antigens to test on sera are to rule in/out…

A

RMSF
typhus
HME
HGE

80
Q

B. quintana transmission

A

louse feces

81
Q

IgG ≥ 256 usually means recent infection

A

Bartonella

82
Q

B. henselae transmission

A
  • cat bites/scratches
  • cat flea
83
Q

Coxiella burnetii transmission

A

infected aerosols

84
Q

2 antigenic variants are tested for (phase I and II of disease)

A

Q fever
C. burnetii

85
Q

hallmark is maculopapular rash beginning on ankles and wrists

A

RMSF

86
Q

RMSF transmission

A

ticks

87
Q

typhus transmission

A

infected fleas’ feces

88
Q

can cause multilineage cytopenias

transmitted by ticks

A

Ehrlichiosis

89
Q

HME

A

human monocytic ehrlichiosis
spotless RMSF
E. chaffeensis

90
Q

HGE

A

human granulocyte ehrlichiosis
A. phagocytophilum