Specimen Collection Flashcards
_____ is not as critical for most molecular testing. The quality of nucleic acids may be compromised if the specimen is ______ handled.
Viability
improperly
DNA and especially RNA will be damaged in ____ or ______. Due to the ____________, it is also important to __________ that could yield false positive results.
lysed or nonviable cells
sensitivity of molecular testing
avoid contamination
Sampling must include material from the ______infection. The time and site of collection should be _____for the likely presence of the infectious agent.
original
optimal
The quantity of target organisms, as well as clinical implications, should be taken into account when interpreting the significance of _________.
Molecular detection can reveal infective agents at levels ______ clinical significance Conversely, _____________ methods may miss detection of a variant organism.
positive results
below
highly specific molecular
Blood draws should go into the proper _________, fi one is to be used.
anticoagulant
________ swabs may be used for throat cultures.
___________swabs with plastic shafts have been recommended for collection of bacteria, viruses, and mycoplasma from mucosal surfaces.
Wooden-shafted swabs
Dacron or calcium alginate
_______are less adherent to the microorganisms and will not interfere with PCR reagents, with the exception of calcium alginate swabs with __________, which had been reported to affect PCR amplification.
Plastics
aluminum shafts
Collection methods such as____________, ______,_______ have been designed for maximum recovery of microorganisms from swabs by centrifugation.
o _________– sterile cups, screw-capped tubes, stoppered tubes, petri dishes
o ________ – calcium alginate swabs, Dacron swabs, cotton swabs, nasopharyngeal-urogenital swabs, swab transport system
o ________ – Neisseria gonorrhoeae transport systems, swab extraction tube system
o ___________ – molecular testing, N. gonorrhoeae transport systems, STAR buffer
o ___________s – Starplex anaerobic transport system (Fisher), BBL vacutainer anaerobic specimen collector
o _________ – BD cellmatics viral transport pack, BBL viral culturette
swab extraction tube system. sonication, and vortex
Sterile containers Swabs Specialty systems Proprietary systems Anaerobic transport system Viral transport systems
Isolating nucleic acids from microorganisms is similar to
isolating nucleic acids from _______ with only a few
additional considerations
human cells
Isolating nucleic acids from microorganisms is similar to isolating nucleic acids from human cells with only a few additional considerations.
o Depending on the microorganism, more________ procedures may be required. Mycobacteria and fungi, in particular, have ____ cell walls that are more difficult to lyse than those of other bacteria and parasites. __________ has a thicker cell wall than gram-negative bacteria and may require more rigorous cell lysis conditions. ______ lacks a cell wall, and so care must be taken with the sample to _________of the cells and loss of nucleic acids.
rigorous lysis thick Gram-positive bacteria Mycoplasma avoid spontaneous lysis
The concentration of organisms within the clinical sample must be considered. Samples can be ________ to concentrate the organisms within the fluid from the __________ that are often received down to volumes that are appropriate for molecular procedures.
centrifuged
milliliters of sample
Inhibitors of enzymes used in molecular analysis may
be present in __________; removal or
inactivation of inhibitors might be included in
_________ methods.
clinical specimens
specimen preparation
If RNA is to be analyzed, _________of
RNases in the sample and in all reagents and
materials that come into contact with the sample is
important.
inactivation or removal
When processing a whole blood specimen, it is
important to remove _______ and other
products of __________because they
can ___________ and thus may ___________ of nucleic acid in the sample, resulting in a _________ PCR result
hemoglobin metabolized hemoglobin inhibit DNA polymerase prevent the amplification false negative
In blood samples, white blood cells are isolated from
the red blood cells using _________ and then
lysed.
Ficoll-Hypaque
Whole blood is processed in _____________, which effectively __________ and other contaminating molecules.
automated DNA isolation systems
remove hemoglobin
__________, devoid of red blood cells, are also
used as sources of microorganism nucleic acid.
Serum and plasma
Sputum is a source of nucleic acid from organisms
that cause ______________. __________ present in sputum may inhibit DNA polymerase and thus must be removed.
respiratory tract infections
Acidic polysaccharide
___________ is treated similarly to cerebrospinal fluid; that is, the specimen is _____________the organisms and then subjected to nucleic acid isolation procedures. Inhibitors of DNA polymerase -_________________________ – have been demonstrated in urine as well.
Urine
centrifuged to concentrate
nitrate, crystals, hemoglobin, and beta-hCG
Any clinical specimen _____ used as a source of
microorganism nucleic acid for analysis.
can be
Depending on the specimen,_______________ may be necessary to allow for optimal nucleic
acid isolation, amplification, and analysis
special preparation procedures
The presence of inhibitors of DNA polymerase has been demonstrated in clinical samples.
Careful separation of nucleic acid from other molecules present in the sample will _____________.
The type of specimen used for molecular testing will also affect extraction and yield of nucleic acid.
Reagents and devices have been developed to combine collection and extraction of nucleic acid from difficult specimens.
ensure target amplification
The presence of inhibitors of DNA polymerase has been
demonstrated in clinical samples.
Careful separation of nucleic acid from other molecules
present in the sample will _____________.
The type of specimen used for molecular testing will also
affect extraction and yield of nucleic acid.
Reagents and devices have been developed to combine
collection and extraction of nucleic acid from _________
ensure target amplification
difficult specimens.
Molecular tests require _______specimen handling and processing for ______ and_____ test results. The success of a test procedure is affected by the ____,_____and ______ of specimens.
optimal
accurate; consistent
age, type, condition
___________– consequence of erroneous or misleading results caused by events that occur prior to sample analysis.
Preanalytical error
Each laboratory will have requirements for specimen handling, but __________ apply to all specimen collection.
The condition of the specimen and the chain of custody is reviewed on__________in the laboratory
general policies
receipt
If a specimen shows evidence of tampering or is hemolyzed, degraded, clotted or otherwise compromised, the technologist must ____________.
notify the superviso
No specimen is accepted___________ and
identification on the specimen tube or container, nor is a
specimen accepted if the labeling on the ______________ that on the accompanying requisition.
without proper labeling
specimen does not match
If a specimen is unacceptable, the ____________ of
the specimen is recorded in the _________ or
laboratory quality assurance records.
disposal or retention
patient report
If not processed immediately, specimens are maintained
in ________________under the appropriate
conditions for the analyte being tested.
secure areas with limited access
For routine specimens tested by ___________,
the entire specimen is often not used. If more than one
test is to be performed on the same specimen, ___________ of specimens is carefully avoided. This can
most likely occur from ________ carryover.
amplification methods
cross-contamination
pipetting
An aliquot removed from a specimen is __________ to
the original tube or vessel. Molecular genetic tests may
require dedicated specimens not shared with other tests.
never returned
________ inhibits enzyme activity. Specimens should be
inspected for visual signs of _________. ________ and
_______ are removed effectively in most DNA and RNA
isolation procedures; however, if white blood cell lysis has
also occurred, DNA or RNA yield will be reduced. This
could result in _______ results in qualitative testing
or _______________in quantitative analyses.
Hemoglobin hemolysis Hemoglobin and coagulants false-negative inaccurate measurements
