Transfusion Transmitted Disease Flashcards

1
Q

Attempts to prevent diseases in donated blood

A

1972 can only accept blood from volunteer (non paid) donors. DHQ and information about high risk lifestyles

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2
Q

Required infectious disease testing (8)

A

HIV, HCV, HBC, HTLV, WNV, Syphillus, Zika and Chaga’s (Bacteria is tested for as well) (Babesia test may be coming out soon)

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3
Q

HIV required testing

A

anti-HIV (IGM and IGG) or anti-HIV+O (IgM +IgG)(either ELISA or ChIA) and HIV NAT (RNA) (PCR or TMA)

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4
Q

HCV testing

A

anti-HCV (IgG) and HCV NAT (RNA)

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5
Q

HBV testing

A

HbsAg, anti-HBc (IgM and IgG) and HBV NAT (DNA)

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6
Q

HTLV

A

(both I and II) anti-HTLV I /II(IgG)

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7
Q

Syphillis

A

Trepanmeal antibody (IgG and IgM) and/or non treponemal RPR testing

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8
Q

WNV

A

WNV NAT (RNA)

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9
Q

Zika

A

Zika Virus NAT (RNA)

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10
Q

Chaga’s disease

A

anti-Trypanosoma cruzii (IgG)

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11
Q

DHQ

A

tries to screen donors for things we do test for with questions (HIV/HCV etc) Tries to screen donors for things we don’t test for (malaria, CJD, vCJD) and does not have any questions for somethings we DO test for (WNV, Zika, HTLV)

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12
Q

Autologous blood collection must be completed…

A

72 hours prior to procedure

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13
Q

ELISA 3 different types

A

enzyme linked immunosorbent assay (Direct, Indirect and Sandwich or capture assay)

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14
Q

Direct EIA

A

(or elisa) is an antigen of interest immobilized and bound to the well and a target antibody with tag is added to the solution

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15
Q

ELISA sensitivity and specificity

A

exteremely sensitive, not a lot of false negatives, however not as specific could have high number of false positives

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16
Q

Chia

A

chemilluminescent immunoassays, variation of colorimetric ELISA test, substrate causes flourescence that reacts with light of certain wavelength

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17
Q

What is the antibody with attached signal molecule that binds in an ELISA assay

A

conjugate antibody

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18
Q

What causes an enzymatic color change in ELIZA

A

substrate

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19
Q

Indirect EIA

A

antigen is immobilized and bound to well/plate, antibody of patient (if present) then binds to antigen,

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20
Q

sandwich EIA

A

Antibody (capture antibody) is bound to well, antigen in the patient binds to these antibody (if present) second conjugate antibody with tag binds to first antibody, chemical change causes colorimetric change for identification

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21
Q

Conjugate

A

conjugated to enzyme that causes indicative change with addition of substrate, antibody that binds either Fc portion of target antibody, or to target antigen

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22
Q

If serologic testing is positive

A

Donor must be deferred, however there is a large percentage of false positives, donor can potentially be eligible for re-entry later

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23
Q

Confirmatory Testing

A

FDA mandates that supplemental or confirmatory testing if available

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24
Q

If initial sample test is reactive:

A

repeat the sample in duplicate, if either of the repeated samples are positive, unit must be discarded and supplemental testing performed if available. IF both repeated samples are negative, unit can be released.

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25
Q

Substrate

A

added at the very end in order to stimulate the enzyme into a colorimetric or fluorescent change for detection

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26
Q

NAT

A

Nucleic acid test, became licensed in 2002 this is highly specific testing, detects either RNA or DNA through amplification of specific nucleotide sequence

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27
Q

MP

A

minipool (about 16 donors) pool the blood together to do NAT testing, can rule out all at once if negative, if positive need to determine which one is positive by repeating NAT individually

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28
Q

Advantage of NAT

A

reduces the ‘window period’ (HIV, HCV, HBV) can detect before antibodies are able to be made (WNV, Zika)

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29
Q

HIV

A

Human immunodeficiency virus, Single stranded RNA, two main types HIV-1 and HIV-2 has several groups (M, N, O and P-most infections worldwide are M ) HIV-2 is less infectious, typically associated west africa. Transmission is 25% infectious- paternal, sexual, blood exposure. Infects CD4 helper T cells

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30
Q

TMA

A

transcription mediated amplification

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31
Q

HIV deferal

A

permanent deferral if antibody and HIV-1 RNA is positive. If serology is negative but HIV-1 RNA is positive-indefinte referral until further testing is done

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32
Q

HIV supplemental testing to anti-HIV 1/2

A

hiv-1 rna can be used as supplemental testing (if negative can use HIV-1 western blot or HIV-1 IFA)

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33
Q

IFA

A

indirect immunoflourecence assay **

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34
Q

With NAT the window for HIV is approximately how many days?

A

9 days

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35
Q

HBV

A

Douple straned DNA hepadnavirus, this virus is much more hardy than HIV and can live on surfaces for weeks . There are two serological markers for this HbsAf and antibody to hepatitis B core antigen. with three markers, result outcome can be complex

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36
Q

Hepatitis B surface antigen

A

detection using either EIA or ChIA, if positve sample repeated in duplicate, if supplemental test result is positive donor is permanently deferred, if not confirmed with supplemental test donor can be reentered in 56 days (8 weeks)

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37
Q

Positive HbsAg negative supplemental tests

A

reentry of donor after 56 days/8 weeks

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38
Q

Supplemental testin for HbsAG

A

HBV-NAT can be used as supplemental i negative or not already being used as supplemental

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39
Q

If anti-Hbc is positive

A

indefinite deferral when positive >1time, permanent deferral if HbsAg is also positive

40
Q

HBV NAT positive

A

permanent deferral if HbsAg is also positive. Indefinite deferral with reentry option if all serological tests are nonreactive

41
Q

NAT negative

A

if negative, only positive is confirmation for other tests, in order to be an acceptable negative results other testing needs to be performed.

42
Q

ANA IFA

A

antinuclear antibodies and Indirect flourescence assay., performed for autoantibodies is autoimmune disorders. SLE almost always positive

43
Q

HCV

A

hepatitis C virus, lipid enveloped single stranded RNA flavavirus, transmission rate is lower than HIV and HBV, same types of transmission. Most infected people develop chronic infection (75-85%) Currently no confirmatory assay except HCV NAT

44
Q

Anti-HCV

A

IgG test ELISA or Chia, HCV NAT is currently the only true confirmation testing available. If HCV NAT is negative it is recommended to perform an alternate manufacturers antibody test for donor counseling

45
Q

HCV NAT positive

A

if anti-HCV is negative, indefinite deferral. Donor may be retested for reentry after 6 months. Permanent deferral if both are positive.

46
Q

HTLV

A

Human T cell lymphotropic virus, enveloped single stranded RNA retrovirus, both HTLV and HIV have reverse transcriptase enzyme, infects T lymphocytes, Transmission: blood, sexual, vertical (especially breast feeding)

47
Q

Parenteral

A

administered or occuring elsewhere in the body than the mouth

48
Q

HTLV associated diseases

A

Adult T-cell leukemia, HTLV associated myelopathy and Tropical spastic paraperesis

49
Q

Myelopathy

A

injury to the spinal chord from trauma or disease etc.

50
Q

HTLV required test

A

IgG antibody to HTLV

51
Q

supplemental testing for HTLV

A

western blot, line assay, IFA or RIPA

52
Q

Positive HTLV

A

1ST occurrence 56 day deferral, 2nd occurrence indefinite deferral

53
Q

Syphilis

A

caused by bacterium Treponema Pallidium, transmission is parental mainly sexual. May indicate high risk behavior

54
Q

Syphilis screening

A

terponemal specific testing: microhemagllutingation (MHA-TP)or EIA. OR non-teronemal markers (RPR, VDRL)

55
Q

Syphilis postive

A

12 month deferral

56
Q

RPR test

A

either solid phase red cell adherance or particle agglutination

57
Q

Syphilis supplemental assay

A

antigen specific immunoflourescence (FTA-ABS, EIA, or MHA-TP)

58
Q

Chaga’s disease

A

caused by parasite, trypanasoma cruzii, carried in feces of triatomine insects (kissing bugs) most often no symptoms, disease can eventually cause cardiomyopathy and/or GI motility problems, vertical transmission is prevalent. Most blood centers test each donor only once

59
Q

Chaga’s positive test

A

indefinite deferral if supplemental test is negative, reentry option is available after 6 months

60
Q

Chaga’s supplemental test

A

ESA (licensed) or RIPA (unlicensed)

61
Q

Chaga’s required test

A

IgG antibody to T. Cruzii through EIA OR Chia

62
Q

WNV

A

single stranded RNA flavivirus, natural cycle in transmission between birds and mosquitos, humans horses and other mammals can be affected

63
Q

Mosquito species that infects

A

Culex mosquitos

64
Q

Symptoms of WNV

A

80% of those infected do not have symptoms, can cause fever, rash, headache and fatigue (1% have severe symptoms, encephalitis/meningitis)

65
Q

Incubation period for WNV

A

2-14 days

66
Q

positive donors

A

presumed viremic positive donors (PVD) are deferred for 120 days

67
Q

Zika Virus

A

single stranded RNA flavavirus

68
Q

Zika virus mosquito

A

Aedes, also carries Dengue, Chikungunya, Yellow fever, also can be trasmitted in utero, perinatal and sexually.

69
Q

Zika symptoms

A

most people are asymptomatic , typical symtoms are fever with maculopapular rash, arthralgia or conjunctivits

70
Q

Zika additonal problems

A

birth defects, causes microcephaly and brain disorders in infants born to mothers who were infected with Zika during pregnancy, also linked to cases of guillian-Barre syndrome in patients after zika infection

71
Q

WNV and ZIKV testing

A

pooled or individual TMA or PCR

72
Q

WNV and ZIKV supplemental testin

A

Repat RNA test (for WNV) , IGM and IGG antibody tests (for both)

73
Q

WNV or ZIKV positive

A

120 day deferral regardless of supplemental test results. Donor is then eligible for reinstatement

74
Q

Babesia

A

caused most commonly by babesia microti-protozoan, tick born disease most common in northeast and north midwest.

75
Q

Testing for Babesia

A

NAT nad antibody tests for detection were licensed in 2018, draft guidance has been issued for testing in selected states

76
Q

CMV

A

cytomegalovirus, present in 40-70% of population, testing all donors is not a requirement, leukoreduction may reduce or prevent post-transfustion CMV infections

77
Q

Other blood born diseases with no FDA licensed test

A

malaria, CJD, vCJD, Dengue, Chikungunya, Leishmaniasis

78
Q

Bacterial Detection in Platelets

A

1 risk is platelets, due to room temperature storage

79
Q

Bacterial risk per platelet

A

1 in 2300, most often it is bacteria contaminants found on the skin

80
Q

Donor reentry process

A

Process for requalification of donors who have been deferred due to false positive results.

81
Q

Donor reentry deferral period

A

2-6 months and most require specific testing to be performed with negative results

82
Q

FDA has issued guidance for reentry for which infectious disease TESTS :

A

Anti-HIV 1/2, Anti-HCV, Hbsag, anti-HBc, Syphilis, HIV/HCV/HBV NAT and Chaga’s antibody

83
Q

testing needed for reentry

A

usually involves performing on a new sample the original serologic test if available and a discriminatory NAT if applicable

84
Q

anti-HCV and HCV NAT reentry

A

after 6months of deferral, test follow up sample with HCV NAT and two different licensed anti-HCV screenign tests

85
Q

Upon reentry HCV NAT test positive

A

defer donor permanently regardless of what ant-HCV test result

86
Q

Upon reentry HCV NAT negative, anti-HCV positive with both tests

A

defer donor permanently

87
Q

Upon reentry HCV NAT nonreactive, one anti-HCV positive and on anti-HCV negative

A

Defer donor and continue follow up

88
Q

Upon reentry HCV NAT negative and both anti-HCV tests negative

A

reenter donor, donor eligible for future donation provided donor meets eligibility criteria

89
Q

Upon reentry any positive test for anti-HBc

A

deferred indefinitely

90
Q

Upon reentry any positive test for anti-HBc

A

minimum of 8 weeks after initial positive test and deferral, donor may apply for reentry, if any positive test donor is deferred indefinitely

91
Q

Donor reentry anti-HBc test positive process

A

minimum of 8 weeks after solely repeatedly reactive (RR) anti-HBc positive test, patient can be tested for reentry.. Follow up sample can be drawn and tested using FDA licensed testing HbsAG, anti-HBV and HBV NAT

92
Q

HBV immunization markers

A

can be present from the HB vaccine for several weeks after given, you could falsely test positive if given the vaccine and be deferred

93
Q

HBsAg

A

An antigen that indicates the presence of Hepatitis B virus. A positive test for HBsAg indicates active Hepatitis B infection

94
Q

HBV NAT positive indicates:

A

A blood test that detects the presence of nucleic acids specific to Hepatitis B virus. A positive test indicates active Hepatitis B infection.

95
Q

HBsAg and anti-HBc, which is the first marker

A

HBsAg rises quicker in the patient and is the first detectable marker of HBV infection

96
Q

anti-Hbs

A

arises after Anti-Hbc and anti-Hbe