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Microbiology 2 > Routine specimen collection > Flashcards

Routine specimen collection Flashcards

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1
Q

Specimen guidelines

A

lab adheres to guidelines from

  • World Health Organization (WHO)
  • Clinical and Laboratory Standards Institute ( CLSI)
  • Accreditation standards

specimen quality must be assessed by lab staff before analytical process

specimens ( non precious) that do not meet acceptability criteria will not be processed

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2
Q

Laboratory staff responsibilities

A
  • most specimens arent collected by lab staff
  • lab are responsible for:
  • safety considerations
  • collection site selection
  • collection procedure
  • specimen transport
  • criteria for acceptable specimens
  • labelling directions
  • requisitions details
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3
Q

time of collection

A

> Some specimens require a specific or preferred time of collection

> Acute Phase of Infection - Some pathogens are more likely to be detectedduring the early stage of the disease/infection
Ex. Enteric pathogens (Salmonella, Shigella spp) are highest in the diarrheal stage

> Prior to Antimicrobials - Specimens should be collected before the commencement of antimicrobial therapy
- Antimicrobials kill some pathogens very quickly and prevent them from being recovered
Ex. Neisseria gonorrhoeae

> Specific Instructions - Procedures that will increase the yield of bacteria
Ex. Urethral swabs collected at least one hour after urination (Chlamydia Trachomatis)

> Time of Day - First morning collection is the best time for collecting some specimens
Ex. Urine

> Intervals - Some specimens require multiple collections
Ex. Blood cultures may require repeat collections
Ex. Stool samples may require multiple collections ( 3 consecutive )

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4
Q

Specimen site

A

> Specimens should be collected from the appropriate body site

Ex. Sputum Specimen- Require lung material therefore require a deep cough for collection (not spit)
Ex. Blood Cultures - Often require multi-site collections (left and right arm)

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5
Q

Contamination

A

> Collection sites may contain normal flora (ex. skin and mucosal )

> collected to minimize microbial contamination
Ex. Wound Material - Surrounding area decontaminated with antiseptic
- Material collected deep within the infected area

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6
Q

specimen types ( tissue samples)

A

need to be kept moist ( sterile saline)

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7
Q

specimen types ( aspirates)

A
  • Material collected with a needle and syringe

- Must be placed in the correct collection container

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8
Q

specimen types ( swabs)

A
  • promptly place in transport media
  • use appropriate type of swab ( cotton, polyester rayon, calcium alginate )
    ex. N. gonorrhoeae is inhibited by cotton & require polyester ( dacron) or rayon for collection
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9
Q

Other types of specimens besides tissue, aspirates and swabs

A
  • Blood (ex. Blood Cultures)
  • Normally Sterile Body Fluids (NSBFs) (ex. Joint fluid, CSF)
  • Sputum
  • Feces
  • Urine
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10
Q

patient collected specimens

A
  • Some specimens are collected by patients themselves
  • Detailed instructions (verbal and written) should be provided to the patient and attached to the collection device and/or container
  • Do not assume the patient knows how to collect the specimen

Ex. Urine, Sputum, Stool

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11
Q

specimen collection quantity

A
  • insufficient volumes may cause false negs

ex. adult blood cultures require a 10ml/ collection site

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12
Q

specimen containers

A
  • if not collected in appropriate container or is damaged/leaked may be rejected
  • conatiners should be sterile and leakproof
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13
Q

Labels ( how to )

A

specimen labels

  • patients full name
  • second approved identifier ( MCP#, Hospital card#, assigned specimen)
  • the name. initials or computer mnemonics of the person collecting
  • date & tiem collected
  • anatomical site & source of specimen if applicable

-label immediately after collection
- NEVER prelabel specimens ( can cause specimen mix up)
- barcode label may be used
-without all required info its considered mislabeled and will be rejected unless a precious specimen( then it will be corrected by the person who mislabeled & cant be processed until corrected)
-

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14
Q

requisition

A

> Requisitions are an important source of information for lab staff
All specimens must be accompanied by a completed approved requisition
Specimen batches may be used when specimens are shipped from referring labs
Requisitions are to include the following:
- Patient’s full name
- Identification number (ex. MCP)
- Patient location (ex. outpatient, hospital unit)
- Requesting Physician
- Specimen Site
- Date and time of collection
- Requested tests
- Patient history/diagnosis
Requisition details must match specimen label

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15
Q

SPECIMEN TRANSPORT

A

Transport Medium
> Transport media keep organisms viable while at the same
time do not encourage their growth
> Transport medium may be included in some specimen
containers
Ex. Swab Transport Systems

> Key aspects associated with transport media include:
Contain buffers - Maintain pH
Thioglycollate(THIO) - A reducing substance which prevents
oxidization
Semisolid - Low agar concentration minimizes spills and
oxidation
Non-Nutritive - Prevent overgrowth of rapid growers
Charcoal - Neutralize toxic substances in the specimen

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16
Q

transport media

A 
Examples of Transport Media
> Stuart’s medium
> Cary-Blair medium
> Amies medium
> Anaerobic transport medium
> Swab transport medium (commercially prepared)
> Viral transport media
17
Q

Transport Systems

A

> Some specimens may be directly inoculated to culture media at
the time of collection (bedside inoculation)
Ex. Blood, synovial and peritoneal fluids can be inoculated into
blood culture broths
JEMBEC System - Commercial system used for N. gonorrhoeae
- system contains selective agar and CO2 generating tablet
Some specimens may be directly inoculated onto selective media
Ex. Nasopharyngeal swab for B. pertussis, Eye specimens (cornea
scrapings)

18
Q

Preservatives

A

> Preservatives can be used in urine and stool specimens to maintain
the population and morphology of organisms
Urine - Boric Acid - maintain bacteria colony count at room
temperature for 24hrs
Stool - Cary-Blair - maintain bacteria if sample is delayed more than 2
hrs
* Samples for C. diff must be collected without a preservative and kept
refrigerated/frozen

19
Q

Anticoagulants

A

> Used in specimens to prevent clotting
Clotting will make it hard to isolate bacteria that may be bound within the clot
Specimens that may require anticoagulants include blood, bone marrow and
synovial fluid
Some anticoagulants have antimicrobial properties so the type and
concentration are important
Ex.Sodium polyanethol sulfonate (SPS) - Must not exceed a concentration of
0.025% (some Neisseria spp. and anaerobes are inhibited with higher
concentrations)
Heparin often used in viral and Mycobacterium spp. in blood
** Citrate and EDTA should NOT be used for microbiology specimens

20
Q

Transport Time

A

> Specimen transport should not be delayed
Most laboratory tests have defined stability limits
To ensure accuracy in testing, specimens cannot be processed beyond those
stability limits
It is important that all specimens are labelled with the collection time so the
stability can be determined
Specimens received to the lab outside of the acceptable time/stability limits
or not labelled with a collection time will be rejected unless deemed a precious
specimen
If transport is delayed, specimens should be placed in transport media and/or
placed at desired environmental conditions (suitable temperature)

21
Q

Shipping

A

> Federal/Provincial/TDG regulations must be followed when shipping
biohazardous material (ie. specimens)
Specimen must be in a leakproof container (primary)
The specimen container must be sealed with waterproof tape
(parafilm)
The specimen container is wrapped in absorbent material and placed
in a waterproof, unbreakable container or biohazard bag (secondary)
The secondary container and requisition is placed in the shipping
container/bag/box (outer)
The outer container must contain a biohazard label

22
Q

Initial Processing

A

> When specimens arrive in the lab they are accessioned and processed
Specimen Accessioning and Processing includes
- Receiving
- Inspecting
- Entering into the Laboratory Information System
- Assigning a specimen identifying number
- Labelling with barcoded labels
- Sorting
- Processing

23
Q

Receiving Specimens

A 
> When specimens arrive to the lab the are received in the 
Laboratory  Information System
> This allows specimen tracking
> Information that is recorded include:
- Date and time of specimen receipt
- Number/type of specimens
- Who received the specimen(s)
24
Q

Specimen Inspection

A

> Specimen inspection involves comparing the specimen label
with the requisition
The label and requisition must contain the necessary
information and the information on both must match
The specimen is inspected for suitability, stability and
spills/leaks (follows all necessary guidelines)
If guidelines are not met, specimen may be rejected

25
Q

Entering

A

> Specimen and patient information is entered into the laboratory
system/database
Specimen requests are entered (based on the requisition)
Some labs may also use a logbook/paper record

26
Q

assigning

A

> The specimen is assigned a unique specimen number
The specimen number is used for tracking and reporting
*** Receiving, Entering and Assigning may be done in one step

27
Q

Labelling

A

> Once the specimen in entered and assigned a specimen number,
barcoded labels are populated and printed
The labels may be used on the requisitions, primary specimen
container, microscope slides, culture plates, testing kits, etc.
Barcode is scanned at various stages which can be used to track and
locate the specimen
Barcode often provides the information included on the requisition
(allowing paper requisition to be filed/kept in clean areas)

28
Q

sorting

A

> Specimens are sorted based on their:
- Priority (STAT, urgent, routine)
- Specimen Type (urine, blood cultures, fecal, etc.)
- Requested tests
Specimen sorting protocols may differ depending on the lab/site

29
Q

processing

A

> Specimens are distributed and processed as per the request

30
Q

unacceptable specimens

A

> Some unacceptable specimens include:

  • Non-sterile, unlabeled, mislabeled, leaking or improper containers
  • Specimen not suitable for request (Common with Anaerobes)
  • Prolonged transport time
  • Incorrect transport conditions
  • Specimens in formalin
  • Incorrect transport medium
  • Duplicate specimens
  • Obviously contaminated specimens
  • Dry Swabs
  • Insufficient quantity
31
Q

rejection of specimens

A

> Always follow the laboratory protocol when rejecting specimens
General criteria include:
- Notification (patient’s physician or nurse)
- Recollection (if possible)
- Documentation (ALWAYS document)
Reasoning (why the specimen was rejected)
Date & Time (of the rejection report)
Name (of the person who received the report)
Initials (of the technologist)
***Precious Specimens - exceptions often granted - NEVER discard until consultation!

32
Q

specimen priority

A

> Specimens are processed based on their priority
High Priority - most important and must be processed immediately
- specimens that are collected through invasive means
- patients with potentially life threatening infections/diseases
- specimens that may contain environmentally sensitive organisms
- requisitions marked urgent/STAT
Ex. CSF, Blood Cultures, etc.

> Lower Priority - generally “routine” and non-sensitive specimens
Ex. Urine, Stools, Throat Swabs, etc.
Follow the lab protocol when deciding specimen priority
Specimen containers and requisitions are usually marked (bright
sticker/marker) so they stand out as “urgent” or high priority

33
Q
A

> Levels of Specimen Prioritization
LEVELDESCRIPTIONSPECIMENS

1 Critical/Invasive:
 Amniotic fluid, 
Blood, 
Brain, 
CSF, 
Heart valve,
 Pericardial fluid
2 Unpreserved Body fluids(not level 1):
 Bone, 
Wound drainage, 
Feces, 
Sputum, 
Tissue

3 Quantitation:
Catheter tip,
Urine,
Tissue for quantitation

4 Preserved:
Feces and Urine in preservative,
Swabs in holding media

34
Q

specimen storage ( REFRIGERATION )

A

> When specimen processing is delayed, the specimen should be stored as per
the protocol/ideal conditions
Refrigeration - Used to preserve specimens that likely contain normal flora
Ex. Urine, Stools, Sputum
- Some organisms are highly susceptible to cold and should not be
refrigerated
Ex. N. meningitidis, N. gonorrhoeae, H. influenzae,
Shigella spp., S. pneumoniae
`

35
Q

specimen storage ( room temp)

A

> Room Temperature - Many specimens remain stable at RT
Ex. Blood Cultures, CSF, Wound material, Anaerobes,
Genital specimens, Swabs in transport media
- Some specimens should not be left at RT
Ex. Urine (unpreserved)
Incubation(35-370C) - Some organisms require warmer temperatures to ensure
viability
Ex. Blood Cultures, CSF
** Blood cultures and CSF prefer incubation but may stay at RT during transport

Microbiology 2 (22 decks)

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