INFECTIOUS DISEASE SCREENING Flashcards
Whic of the ff testing methods would test a donor’s plasma for infectious antigens or antibodies against infectious disease agents? A. Flow cytometry B. NAT C. Serologic testing D. Direct coombs
C. Serologic testing
Whic of the ff testing methods would test a donor’s plasma for viral nucleic acids (e.g RNA)? A. Flow cytometry B. NAT C. Serologic testing D. Direct coombs
B. NAT - nucleic acid amplification test
True/false - Both serologic testing and NAT require repeat testing of an initially reactive sample to confirm a positive result
False
This only applies to serologic
Repeat NAT is not permitted by FDA
What is the appropriate next step to be taken in the ff scenario? :
A donor sample that was initially reactive withserologic testing has tested reactive/positive with the repeated duplicate testing
A. The donated component should be discarded and the donor be deferred indefinitely
B. Donated units should be discarded
C. Test the individual samples using a more specific assay or using the same method
D. Repeat the testing in duplicate
B. Donated units should be discarded
What is the appropriate next step to be taken in the ff scenario? :
A pool of donor samples tested reactive by NAT
A. The donated component should be discarded and the donor be deferred indefinitely
B. Donated units should be discarded
C. Test the individual samples using a more specific assay or using the same method
D. Repeat the testing in duplicate
C. Test the individual samples using a more specific assay or using the same method
Test individual samples by NAT
What is the appropriate next step to be taken in the ff scenario? :
An individual donor sample tested reactive by NAT for HCV
A. The donated component should be discarded and the donor be deferred indefinitely
B. Donated units should be discarded
C. Test the individual samples using a more specific assay or using the same method
D. Repeat the testing in duplicate
A. The donated component should be discarded and the donor be deferred indefinitely
For Individual specimen testing reactive on an NAT screen for HIV, HCV, or HBV
_________ is a process of identifying, retrieval and quarantine of prior donations from a donor whose current donation is repeatedly reactive on an infectious disease screening test and to notify recepients of possible exposure
Look-back
Which of the ff is more likely the primary cause of residual transmission of infection from donation?
A. A blood collection facility that uses an electronic system to control labeling and releasing of components
B. A blood bank failing to quarantine a unit after being notified of it being positive with an infectious disease
C. A donor who is in the early stages/window period of infection who came to donate blood and tested negative for all infectious diseases
D. Current test kits used by testing facilities do not detect a newer strain of a virus
C. A donor who is in the early stages/window period of infection who came to donate blood and tested negative for all infectious diseases
- in the early stages, the agent cannot be detected by testing; titers may be too low to be detected
Choice A and B - this being the primary cause is rare
D - this is theoretical
_____ is an alternative method of protecting the blood supply from infectious agents for which donor screening tests are not available
Pathogen inactivation
Which of the ff is NOT a form of pathogen inactivation of blood components A. psoralen treatment B. solvent detergent treatment of plasma C. Chromatography D. Irradiation E. cold ethanol fractionation
D. Irradiation
- kills off residual leukocytes, not pathogens
Which of the ff is the most common cause of NANB transfusion related hepatitis? A. HIV B. HBV C. HCV D. HEV
D. HCV
NANB = Non-A, Non-B hepatitis
Which of the ff is the only FDA approved donor test for HTLV infection? A. Western Blot B. IgG antibody screening assays C. RPR D. NAT assays
B. IgG antibody screening assays
HTLV = Human T-Cell Lymphotropic Virus
western blot - used to differentiate HTLV-1 and 2
RPR - for syphilis/ T. palladium
NAT - for presence of viral nucleic acid
Which of the ff is used to test for transfusion infectivity of Hepatitis virus in donors?
Which of the ff is the only FDA approved donor test for HTLV infection?
A. Western Blot
B. IgG antibody screening assays
C. RPR
D. NAT assays
D. NAT assays
- detects viral RNA in plasma
Which of the ff is true about HTLV transmission?
A. leukocyte reduction does not reduce HTLV infectivity because this virus is mainly found in plasma
B. HTLV can be transmitted by all types of blood components
C. HTLV infectivity increases with increased refrigerated red cell storage
D. HTLV cannot be transmitted by frozen or thawed plasma components
D. HTLV cannot be transmitted by frozen or thawed plasma components
- can only be transmitted by white-cell containing components
Choice A - HTLV is cell associated so leukoreduction reduces infectivity
Choice B - only white-cell containing components
Choice C - refrigeration reduces infectivity
True/false - SD treated or pathogen inactivated components are protected from residual Hepatitis E virus transmission
False
- it is NOT susceptible to SD treatment or ay current pathogen inactivation methods
HepE is nonenveloped virus
Which of the ff is NOT an effective method in detecting /preventing bacterial contamination in platelet components?
A. visual inspection by swirling
B. hold and release of component after a negative 12-24 hr culture result
C. using a diversion pouch for the first 10-40 ml of donor blood collection
D. disinfection of donor skin using idiophors before phlebotomy
A. visual inspection by swirling
- this method lacks sensitivity and specificity
Which of the ff methods is used in testing for West Nile virus infections in donor samples? A. ID NAT B. Urine sample C. Enzyme immuno assay D. Serologic antibody testing E. Through donor question screening F. No FDA-approved testing
A. ID NAT
- by ID-NAT (Individual Donor-NAT)
vs. MP-NAT (MiniPool-NAT) - not recommended because cannot detect low levels of circulating viral RNA
What is the recommended method for testing ZIKV infections in donor samples? A. ID NAT B. Urine sample C. Enzyme immuno assay D. Serologic antibody testing E. Through donor question screening F. No FDA-approved testing
B. Urine sample
Donors who have visited endemic areas are advised to self defer for 28 days
How long is the deferral period for donors who had a reactive testing by NAT and/or with diagnosis for ZIKA virus infection?
120 days
true/false - pathogen inactivation has been shown to be effective for reducing transmission of ZIKA virus titers
True
What is the recommended method for testing T. cruzi (Chaga's disease) infections in donor samples? A. ID NAT B. Urine sample C. Enzyme immuno assay D. Serologic antibody testing E. Through donor question screening F. No FDA-approved testing
C. Enzyme immuno assay
supplemental test used is enzyme strip assay (ESA) which is FDA approved
true/false - chagas disease/T.cruzi infections have a higher transmission rate in refrigerated components (e.g RBCs) compared to platelet / fresh / room temp components
False
The parasite has limited survival in refrigerated components; transmission only documented in plt component
What is the recommended method for testing Babeosis infections in donor samples? A. ID NAT B. Urine sample C. Enzyme immuno assay D. Serologic antibody testing E. Through donor question screening F. No FDA-approved testing
E. Through donor question screening - asked for history of infection
F. No FDA-approved testing
How long is the deferral period for donors who have had a history of babeosis?
Pemanent / indefinite deferral
What is the recommended method for testing malaria infections in donor samples? A. ID NAT B. Urine sample C. Enzyme immuno assay D. Serologic antibody testing E. Through donor question screening F. No FDA-approved testing
E. Through donor question screening - asked for history of infection
F. No FDA-approved testing
true/false - pathogen inactivation has been shown to be effective for reducing transfusion transmission of malaria
true
What is the recommended method for testing for prion infections (e.g CJD risk) in donor samples? A. ID NAT B. Urine sample C. Enzyme immuno assay D. Serologic antibody testing E. Through donor question screening F. No FDA-approved testing
E. Through donor question screening - asked for history of infection
F. No FDA-approved testing
What is the recommended method for testing parvovirus B19 infections (e.g CJD risk) in donor samples? A. NAT B. Urine sample C. Enzyme immuno assay - D. Serologic antibody testing E. Through donor question screening F. No FDA-approved testing
A. NAT - used on pooled donor samples
Which of the ff viral agents is NOT susceptible to SD treatment or physical inactivation? A. HBV B. HIV C. Parvovirus B19 D. T. cruzi
C. Parvovirus B19- can persist in plasma products
true/ false - Pathogen inactivation by SD treatment and methylene blue/light treatment damages red cell membranes, thus they are only used on plasma and platelet products.
False
used only for plasma; these treatment damages cell membranes in platelets as well
How does pathogen inactivation work/ what does it target?
targets nucleic acids; the technology of inactivation generates cross linking, preventing pathogen replication
