Specimen Collection, Storage, and Shipment
Collecting and shipping specimens for suspected measles cases
CDC recommends that a throat swab specimen and a blood specimen be collected from all patients with clinical features compatible with measles.
When sending specimens for testing please contact your health department to determine where to submit specimens and how to ship them.
Please be sure to provide:
- Contact name with telephone number and email address
- Type of virus specimen and date collected
- Date serum sample collected
- MMR vaccination history [date(s) if known]
- Clinical signs and symptoms
- Patient’s date of birth or age
- Rash onset date
Centers for Disease Control and Prevention
STAT Unit #81
Attn: Dr. Paul Rota
1600 Clifton Road NE
Atlanta, GA 30329
Contact Paul Rota for additional information and to provide shipment details.
Serology (serum samples)
Collect the first (acute-phase) serum sample as soon as possible upon suspicion of measles disease. If the acute-phase serum sample collected ≤3 days after rash onset is negative, and the case has a negative (or not done) result for RT-PCR, a second serum sample collected 3–10 days after symptom onset is recommended because, in some cases, the IgM response is not detectable until 3 days after symptom onset.
Store specimens at 4°C and ship on wet ice packs.
Throat or nasopharyngeal swab samples
Detection of measles RNA and measles virus isolation are most successful when samples are collected on the first day of rash through the 3 days following onset of rash. However, virus may still be recovered by cell culture through day 10 following rash onset. Detection of measles RNA by RT–PCR may be successful as late as 10-14 days after rash onset. Collect throat or nasopharyngeal swab samples as soon as measles disease is suspected. RT-PCR has the greatest diagnostic sensitivity when samples are collected at first contact with a suspected case.
A commercial product designed for the collection of throat specimens or a flocked polyester fiber swab can be used. Synthetic swabs are preferred over cotton swabs, which may contain substances that are inhibitory to enzymes used in RT-PCR. Flocked synthetic swabs appear to be absorbent and elute samples more efficiently.
Swabs should be placed in 2 ml of standard viral transport medium (VTM) . Allow the swab to remain in VTM for at least 1 hour (4°C). Ream the swab around the rim of the tube to retain cells and fluid in the tube. The swab can be broken off and left in the tube or discarded.
Storage and shipment: Following collection, samples should be maintained at 4°C and shipped on cold packs (4°C) within 24 hours. If there is a delay in shipment, the sample is best preserved by freezing at −70°C. Frozen samples should be shipped on dry ice.
Processing the swabs within 24 hours of collection will enhance the sensitivity of both the RT-PCR and virus isolation techniques.
- Cell culture medium (minimal essential medium or Hanks’ balanced salt solution) or other sterile isotonic solution (e.g. phosphate buffered saline) can be used. The presence of protein, for example 1% bovine albumin, 0.5% gelatin, or 2% serum, stabilizes the virus. Samples without a source of protein in the medium will lose 90%–99% infectivity within 2 hours at 4°C.
A minimum volume of 50 ml of urine should be collected in a sterile container and then processed by centrifuging at 2500 × g for 15 minutes at 4°C. The sediment should be resuspended in 2 ml of VTM.
Storage and Shipment: Store urine sediment in VTM at 4°C and, if possible, ship on cold packs within 24 hours. The best method for preserving measles virus in processed (centrifuged) urine is to freeze the sample at −70°C and ship on dry ice.