CARIBBEAN EPIDEMIOLOGY CENTRE

 

CAREC Guidelines on specimen collection for

Severe Acute Respiratory Syndrome (SARS)

Collection of Clinical specimens

The success of laboratory diagnosis largely depends on the quality of the specimen, condition for transport and storage of specimen before it is processed in the laboratory.

 

• Specimens for isolation in culture and antigen detection should generally be taken during the first 3 days after onset of clinical symptoms.
• Specimens should be collected and transported in a suitable transport media such as physiological saline solution phosphate- buffered saline and Hamks balanced salt solution. They should be supplemented with 0.5 -1% of bovine serum albumin (BSA) or gelatin and 0.2% ml gentamice sulphate solutions (50mg/ml)
• Specimens should be refrigerated immediately after collection and transported to the laboratory within 48 hours
• Specimens should be accompanied with the relevant clinical and epidemiological information.

Procedures for specimen Collection

Clinical specimens should be collected as described below and added to transport media.

Nasopharyngeal swabs: 

• Insert a sterile swab beneath the inferior turbinate of either nostrils and leave in place for few seconds.
• Slowly withdraw with a rotating motion against the mucosal surface of the nostril
• Repeat the same procedure in the other nostril using a new sterile swab
• The tip of each swab should be collected in a vial containing 2-3 ml of viral transport media (VTM), with the applicator stick broken off.

Throat swabs:

• Both tonsils and posterior pharynx should be vigorously swabbed.
• The swab is collected into a vial containing 2-3 ml of viral transport media (VTM), with the applicator stick broken off.

Nasopharyngeal aspirates

• Nasopharyngeal secretions are aspirated through a catheter connected to a mucus trap and fitted to a vacuum source.
•  The catheter is inserted into a nostril parallel to the palate. Then the vacuum is applied and the catheter is slowly withdrawn with a rotation motion.
• Mucus from the other nostril is collected with the same catheter in similar manner.
• After mucus has been collected from both nostrils, the catheter is flushed with 3 ml of viral transport media (VTM).

Sputum:

• Obtain sputum by deep cough either spontaneously or following mechanical induction using a throat swab.
• Collect in a sterile cup.

Urine.

• Midstream urine should be collected into a sterile container.
• The urine should then be centrifuged for 30 min.
• The supernatant discarded, and the sediment resuspended in 1-2 ml of viral transport media (VTM).

Postmortem specimens

• In fatal cases, lung tissue and heart blood should be collected.
• Lung tissue should be divided, and half should be keep fresh and the other half placed in formalin.

Sera collection:

• An acute phase serum specimen (3-5 ml of whole blood should be taken soon after onset of clinical symptoms but not later than 7 days,
• A convalescent phase serum specimen should be collected 2 to 4 weeks later. Single serum specimens cannot be used for individual diagnosis.

Should you encounter a suspected or probable case of SARS and need further advice with respect to sample collection, transport or testing please contact:

Dr. Rosa Salas

Virologist

CAREC

Tel: 868-622-4261 ext 221 or 248

Fax: 868-622-2792

E-mail: salasros@carec.paho.org