1.         General Procedure For Submission Of Specimen

            The reader is referred to the tables for appropriate specimens for the diagnosis of viral infections.  The specimens are indexed to various clinical syndromes, which are organized into related groups.

            Specimens for isolation, or direct detection methods should be obtained as soon as possible after onset of symptoms.  The specimens must be placed in a suitable container, packed with ice, and sent to the laboratory immediately after collection. The package of flask containing the specimen must be marked with the words “PATHOLOGICAL SPECIMEN – FRAGILE”.

Every specimen must be accompanied by a completed request form giving full particulars of the patient, the specimen and the required examinations. For proper interpretation of serological results, it is essential to know the date of the disease and the date the specimen is collected.

            A telephone call informing the laboratory of the despatch of specimen(s) in ice, will ensure prompt attention on arrival.  For further information, please call: 03-40402345 / 346 and speak to the medical officer.

2.         Specimen Collection And Preparation

2.1        Specimens for Isolation

            In general, viruses are unstable at temperature above 4^oC; specimens should, therefore be sent in ice and reach the laboratory as soon as possible after collection.

            Specimens which are to be placed in a thermos flask packed with ice must be enclosed in a watertight container (e.g. a  polythene  bag) to prevent flooding of the specimens by the melting ice.   The lid of the flask should be sealed with adhesive tape. Properly sealed specimens may be sent in a plastic bag packed with ice if they can reach the laboratory within a few hours of collection. In cases where chilling is not required, the containers should be packed with sufficient absorbent material in a strong box to prevent damage during transport.

i.          Blood :

As early as possible in the illness, collect aseptically 5-10 ml of blood (3-5 ml for children). Chill the  blood and send it to the virus laboratory as soon as possible.

ii.          Brain tissue for viral diagnosis:

Remove portions, about 1.5 cm cube, of various parts of the brain and the upper spinal cord with as little contamination as possible. Place them in a sterile  container and transport in ice as soon as possible.

iii.         Brain tissue for rabies :

Remove the whole brain as soon as possible after death; great care must be taken to avoid accidental infection. Carefully cut into half, antero-posteriorly, with a long-bladed knife; avoid crushing and tearing of tissue.  Place one half in Zenker-acetic fixative and the other in 50% glycerol-saline or on ice if it can reach the laboratory within a few hours.

iv.         Cerebrospinal fluid (CSF):

Aseptically collect 1-3 ml into a sterile container. Keep the  specimen chilled at all times.

v.         Conjunctival scraping: 

Collect the scraping in a screw-capped test-tube containing COLD transport medium, which is available at the Division of Virology.  Keep the specimen chilled at all times.

vi.         Eye swab: 

Firmly rub the lesion with a sterile swab, which has been moistened with nutrient broth or sterile distilled water.  DO NOT MOISTEN SWAB WITH NORMAL SALINE.

vii.        Faeces: 

Collect faeces in a 5ml bottle as soon as possible after voiding.  Keep it chilled at all times.

viii.       Genital swab: 

Firmly rub the lesion with a sterile swab, which has been moistened with nutrient broth or sterile distilled water.  DO NOT MOISTEN SWAB WITH NORMAL SALINE.

ix.         Lacrimal tears (preferable to eye swab): 

Instruct the patient to sit in an inclined position.  Tilt his head to allow the tears to flow to the outer corner of his affected eye.  (If necessary, stimulate flow of tears by teasing the cornea gently with a dry sterile swab.  Ask the patient to look slightly upwards and inwards.  He may blink during the process.)  Apply the tip of a 10 – 20 ul capillary tube to the corner of the eye where the tears have accumulated in a pool and collect the tears without touching the eye.  Tap the tube to shift the tears to the central portion of the tube. Seal both ends of the tube with plasticine.  Tape the tube onto a card with the patient's particulars.  Send it to the laboratory immediately, otherwise freeze it and transport it in ice to the laboratory as soon as possible.

x.         Saliva: 

Collect about 10 ml of saliva with a pipette and place it in a bottle.  Seal the bottle, pack it in ice and sent it to the laboratory by the quickest route possible.

xi.         Throat swab: 

Ask the patient to cough and swab the mucus coughed out.  Transfer the swab into a tube containing CHILLED broth.  Repeat the procedure with a second swab and place it into the same tube with the first.  Keep the specimens chilled at all times.

xii.        Vesicle fluid and scraping: 

Clean the tops of several vesicles with ether or alcohol and allow them to dry before proceeding.  Puncture the vesicles using a sterile needle and collect the fluid into sterile capillary tubes.  Next, gently scrape off the bases of the vesicles (avoid bleeding) with a sterile scalpel and make smears of the scrapings on two clean glass-slides.  Dry the smears in air and fix.

2.2.       Specimens for Rapid Diagnosis e.g. Antigen Detection

            For the investigation of respiratory tract infection, nasopharyngeal secretions (NPS) are, by far, the best.  Collection of this specimen is done by passing a fine catheter through the nose into the nasopharynx and applying suction, thereby collecting the NPS in a mucus trap.  Transport the specimens as quickly as possible to the nearest hospital or clinical laboratory for processing and preparation of slides for despatch to the virus laboratory.  If delay is anticipated, add 1 ml viral transport media to the specimen and transport it in ice.

            Swabs and vesicle fluid for direct antigen detection are collected in the same way as for virus isolation.  The specimens must be kept chilled during storage and transport.

2.3.       Specimens for Serology

            Since the diagnosis is based on the appearance of, or increase in, antibody titre during the course of the infection, at least two, and sometimes more, specimens of blood at different stages of illness are required.  The first specimen should be taken as early as possible after onset of illness and the second, in general, should be taken 10 – 21 days later.  If the patient is discharged earlier, the second specimen should be taken on the day of discharge, in case it cannot be obtained on the optimum day after the patient has been discharged.

            In viral disease, 5 – 10 ml of blood for serological tests must be taken aseptically and put  in a plain bottle.  The blood or serum specimen may be sent without chilling provided it can reach the laboratory within 24 hours of collection, otherwise the specimen must be sent in wet ice.  Do not freeze whole blood as this causes haemolysis. 

2.4.       Specimens for genome detection by the polymerase chain reaction (PCR)

HIV-cDNA (Human immunodeficiency virus complementary DNA) PCR:

Collect  2.5 ml of blood  in EDTA. Specimen must  be transported within 48 hours after collection  in ice or at ambient temperature.  Do not freeze.

Hepatitis B PCR, Hepatitis C PCR, Dengue PCR, Japanese Encephalitis PCR: Collect 5.0 ml of blood into a plain sterile tube or collect 5.0 ml of blood and aliquot 2.5 ml into two EDTA tubes.  Specimen should  reach the laboratory within 24 hours after collection. If delay is unavoidable pack the specimen in a flask or box containing ice or ice packs.

3.         Materials Obtainable From The Division Of Virology

a)         Viral Transport media is to be used to transport specimens such as skin lesions, mucosal  lesions, throat swabs, rectal swabs etc.

4.         SPECIMENS FOR VIROLOGY

FORMS

  HIV Ante Natal request form

  HIV Serology request form

  HIV PCR request form