COLLECTION AND TRANSPORT OF VIROLOGICAL
SPECIMENS.
o In the investigation of viral infections, reliable laboratory results can
only be obtained if the specimens are collected, preserved and
transported correctly to the Virology laboratory.
o When to collect virological specimens?
 Specimen for detection of viruses should be collected as soon as
possible after the appearance of the symptoms that is when the
concentration of the virus is at its highest.
 Blood for antibody testing should be collected as early in the disease as
possible and also 5- 10 days later.
 Two serum specimens (paired sera) are necessary to detect a rise in the
titre of the Ab. A four fold rise in titre between paired sera establishes a
positive result.
o Collection of virological specimens:
 The type of the specimen required will depend on:
1. The viral infection suspected.
2. The laboratory technique to be used.
 District and local laboratories must obtain information about the
collection of specimen from their Virology Reference Laboratory.
The following information is intended only as a general guide:
1. Faeces:
1. Place about 4-8 g of faeces (small spoon) in a clean, dry, leak-proof
container (not a waxed carton).
2. Deliver to the laboratory as soon as possible.
3. If there is likely to be a delay to more than few hours in the specimens
reaching the laboratory, suspend about one gram of faeces in 9 ml of
phosphate buffered saline. If possible centrifuge at 2000g for 15
minutes, and then transfer the supernatant fluid to a clean leak- proof
container.
4. Label and keep at -20 OC.
5. Send to the virology laboratory in a cold box.
6. If a faeces sample can not be obtained, rectal swab should be collected
and transported in buffered saline.
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7. The isolation of viruses from rectal swab however, is less satisfactory
than from faeces.
8. Faeces specimens are required to diagnose viral gastroenteritis specially
that caused by rotaviruses, and to investigate poliomyelitis and other
diseases caused by enteroviruses.
2- Nasopharyngeal secretions:
a- Collect a specimen by passing a sterile cotton wool swab, attached to a
pent piece of thin wire, through the floor of the nasal cavity as far as the
nasopharynx.
b- After few seconds, slowly withdraw the swab and immerse the swab in
a container of sterile VTM, cutting off swab wire to allow the bottle cap
to be replaced tightly.
c- A specimen of nasopharyngeal secretion can also be obtained by using
a sterile mucus extractor.
d- Respiratory viruses can also be recovered from a throat swab preserved
in VTM but a pernasal swab is usually easier to obtain and has been
found very satisfactory for the isolation of influenza viruses, measles
virus, and respiratory syncytial viruses.
e- A throat swab is unsuitable if the specimen is to be tested by a
fluorescence antibody technique.
f- Nasopharyngeal specimens are required to diagnose respiratory
syncytial virus infection, and when necessary to investigate infections
caused by influenza and parainfluenza viruses, measles, rubella virus,
adenoviruses, and enteroviruses.
3. Cerebrospinal fluid:
a- Collect 0.5- 1.0 ml of fluid in a dry, sterile, leak-proof container.
Refrigerated immediately at 4 OC.
b- Transport in an insolated cold box.
c- Cerebrospinal fluid is required to investigate some arbovirus infections.
When meninges are infected, the CSF will contain lymphocytes and the
CSF total protein will be raised.
4. Skin and ulcer specimens:
a- Collect skin scrapings in a dry sterile container.
b- Refrigerate immediately at 4OC, and then transport in a cold box.
c- If measles or rubella is suspected, the virus is more likely to be isolated
from a pernasal swab.
d- Skin specimens are required to investigate infections caused by herpes
simplex viruses, rabies viruses….
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5. Blood for serological tests:
a- Two serum specimens are required to diagnose an infection
serologically.
b- Collect the sample within 5 days of the onset of the symptoms, and the
second sample 5-10 days later.
c- Collect 5-10 ml of venous blood in a dry sterile, screw-cup glass tube or
bottle.
d- A single sample is required for investigating newborn infant with
congenital defects, determining immunity to rubella or other viruses…
e- A single serum sample is required when testing for hepatitis B surface
Antigen (HBsAg) and HIV-1 and HIV-2.
f- After the blood collected, collect in leak-prove container, refrigerate at
4OC until transport it in ice box to the virology lab.
6. Anticogulated blood for culture:
a- Collect 7-10 ml of blood into a sterile tube or bottle which contains
heparin, gently mix the blood with the anticoagulant.
b- Viruses which can be cultured from blood include dengue viruses and
some arboviruses.
7. Specimens such as urine and sputum are generally unsuitable for
viruses' isolation.
All samples which may contain dangerous and highly
infectious viruses must be labeled HIGH RISK with a red
marker pen, and handled with great care.
 Labeling of specimens:
This should be including:
 Patient's name and number.
 Hospital or health centre.
 Type of specimen.
 Date and time of collection.
 Container tops should be sealed with adhesive tape to prevent slacking
during transit.
 Information to accompany specimens:
A request form should include the fallowing information:
1. Name, place, age, number of the patient, and details of any recent travel.
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2. Type of specimen, if two, mention as the first of second.
3. Investigation required.
4. Full clinical information: nature duration, and severity of disease.
5. Details about immunization and antimicrobial therapy.
6. Name and address of the hospital or health centre.
*IF THE SAMPLE IS HIGH RISK, THE SAME SENTENSE SHOULD
BE WRITTEN IN THE FORM BY THE RED COLOR PEN.
 The form should not be wrapped around the specimen container but
placed separate it, inside the outer container where it will be found
immediately when the package is opened.
Transporting of specimens to the Virology laboratory:
 Viruses are unable to survive temperature over 50 OC, freezing or
fluctuatings in temperature.
 Viruses can also be damaged be light, drying, change in pH, and
bacterial enzymes.
 The usage of VTM will prevent specimens from drying out and help to
preserve viral activity.
 All virological specimens should be transported in ice box with the
warning label.
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