Education

1. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Collection, handling and
transportation of the Specimens
By :TA Maab Abdalla

2. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Learning objectives
At the end of the presentation, participants should und
erstand the:
• Procedures, preparation, processing and transpo
rt of specimens

3. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Successful laboratory investi
gations
 Advance planning
 Collection of adequate and appropriate specimens
 Sufficient documentation
 Biosafety and decontamination
 Correct packaging
 Rapid transport
 Choice of a laboratory that can accurately perform the tests
 Timely communication of results

4. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Specimen collection:
key issues
Consider differential diagnoses
Decide on test(s) to be conducted
Decide on clinical samples to be collected to conduct th
ese tests
• consultation between microbiologist, clinicians and epi
demiologist

5. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Transport medium
Allows organisms (pathogens and contaminants) to su
rvive
Non-nutritive - does not allow organisms to proliferate
For bacteria – i.e., Cary Blair
For viruses - virus transport media (VTM)

6. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Blood for smears
Collection
Capillary blood from finger prick
• make smear
• fix with methanol or other fixative
Handling and transport
Transport slides within 24 hours
Do not refrigerate (can alter cell morphology)

7. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Blood for cultures
Collection
Venous blood
• infants: 0.5 – 2 ml
• children: 2 – 5 ml
• adults: 5 – 10 ml
Requires aseptic technique
Collect within 10 minutes of fever
• if suspect bacterial endocarditis: 3 sets of blood culture

8. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Blood for cultures
Handling and Transport
Collect into bottles with infusion broth
• change needle to inoculate the broth
Transport upright with cushion
• prevents hemolysis
Wrap tubes with absorbent cotton
Travel at ambient temperature
Store at 4oC if can’t reach laboratory in 24h

9. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Serum
Collection
Venous blood in sterile test tube
• let clot for 30 minutes at ambient temperature
• glass better than plastic
Handling
Place at 4-8oC for clot retraction for at least 1-2 hours
Centrifuge at 1 500 RPM for 5-10 min
• separates serum from the clot

10. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Serum
Transport
4-8oC if transport lasts less than 10 days
Freeze at -20oC if storage for weeks or months befo
re processing and shipment to reference laboratory
Avoid repeated freeze-thaw cycles
• destroys IgM
To avoid hemolysis: do not freeze unseparated bloo
d

11. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Collection
Lumbar puncture
Sterile tubes
Aseptic conditions
Trained person
Cerebrospinal fluid (CSF)

12. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
CSF
Handling and transportation
Bacteria
• preferably in trans-isolate medium, pre
-warmed to 25-37°C before inoculation
OR
• transport at ambient temperature (relevant pathogens do no
t survive at low temperatures)
Viruses
• transport at 4-8oC (if up to 48hrs or -70oC for longer duratio
n)

13. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Stool samples
Collection:
Freshly passed stool samples
• avoid specimens from a bed pan
Use sterile or clean container
• do not clean with disinfectant
During an outbreak - collect from 10-20 patients

14. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Rectal swabs
Advantage
• convenient
• adapted to small children, debilitated patients and othe
r situations where voided stool sample not feasible
Drawbacks
• no macroscopic assessment possible
• less material available
• not recommended for viruses

15. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Stool samples for viruses
Timing
• within 48 hours of onset
Sample amount
• 5-10 ml fresh stool from patients (and controls)
Methods
• fresh stool unmixed with urine in clean, dry and sterile container
Storage
• refrigerate at 4oC; do not freeze
• store at -15oC - for Ag detection,polymerase chain reaction (PCR)
Transport
• 4oC (do not freeze); dry ice for (Ag detection and PCR)

16. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Stool samples for bacteria
Timing
• during active phase
Sample amount and size
• fresh sample and two swabs from patients, c
ontrols and carriers (if indicated)
Method
• Cary-Blair medium
• For Ag detection/PCR – no transport medium
Storage
• refrigerate at 4oC if testing within 48 hours, -70oC if longer; st
ore at -15oC for Ag detection and PCR
Transport
• 4oC (do not freeze); dry ice for Ag, PCR detection

17. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Stool samples for parasites
Timing
• as soon as possible after onset
Sample amount and size
• at least 3 x 5-10 ml fresh stool from patients and controls
Method
• mix with 10% formalin or polyvinyl chloride, 3 parts stool to
1 part preservative
• unpreserved samples for Ag detection and PCR
Storage
• refrigerate at 4oC; store at -15oC for Ag detection and PCR
Transport
• 4oC (do not freeze); dry ice for antigen detection and PCR

18. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Throat swab
(posterior pharyngeal swab)
Hold tongue away with tongue
depressor
Locate areas of inflammation
and exudate in posterior
pharynx, tonsillar region of
throat behind uvula
Avoid swabbing soft palate; do
not touch tongue
Rub area back and forth with
cotton or Dacron swab
WHO/CDS/EPR/ARO/2006.1

19. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Nasopharyngeal swab
Tilt head backwards
Insert flexible fine-shafted pol
yester swab into nostril and ba
ck to nasopharynx
Leave in place a few seconds
Withdraw slowly; rotating moti
on
WHO/CDS/EPR/ARO/2006.1

20. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Naso-pharyngeal aspirate
Tilt head slightly backward
Instill 1-1.5 ml of VTM /sterile n
ormal saline into one nostril
Use aspiration trap
Insert silicon catheter in nostril
and aspirate the secretion gent
ly by suction in each nostril
WHO/CDS/EPR/ARO/2006.1

21. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Sputum
Collection
Instruct patient to take a deep breath and cough up s
putum directly into a wide-mouth sterile container
• avoid saliva or postnasal discharge
• 1 ml minimum volume

22. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Respiratory samples
Handling and Transport
All respiratory specimens except sputum are transported in app
ropriate media
• bacteria: Amie’s or Stuart’s transport medium
• viruses: viral transport medium (VTM)
Transport as quickly as possible to the laboratory to reduce ove
rgrowth by oral flora
For transit periods up to 24 hours
• ambient temperature for bacteria
• 4-8°C for viruses

23. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Collection
Biopsy relevant tissues
• place in formalin for histopathology
• place in transport medium for microbiological testing
• place in sterile saline for isolation of viral pathogens
Post-mortem samples

24. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
Post-mortem samples
Handling and transportation
Fixed specimens can be transported at ambient temperatur
es
• transport specimens in transport media within 24h at am
bient temperature
• transport specimens in sterile saline at 4-8oC within 48h

25. E P I D E M I C A L E R T A N D R E S P O N S E
Laboratory Training for Field Epidemiologists
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