should be tested for suspected mumps
virus can cause illness with an acute onset
of unilateral or bilateral tender, self-limited
swelling of the parotid or other salivary
gland, lasting 2 or more
days, without other apparent cause.
diagnosis of mumps may be unreliable,
suspected cases of mumps should be
laboratory confirmed. As with any
disease, lab work should be used in
conjunction with clinical presentation
(signs and symptoms). The recommendation
to laboratory confirm all cases will
be re-evaluated as the outbreak progresses.
should not be ruled out in someone
with negative laboratory tests who
is vaccinated if they have symptoms
consistent with mumps.
detailed investigation should be conducted
for each case with emphasis on accurate
and complete immunization history.
Recent outbreaks have included many
cases who had already received at
least one dose of mumps-containing
What is the clinical case definition for mumps?
illness with acute onset of unilateral
or bilateral tender, self-limited swelling
of the parotid or other salivary gland
lasting 2 or more days, and without other
is a confirmed case of mumps?
Confirmed mumps cases are:
- laboratory confirmed or
- meet the clinical case definition
and are epidemiologically linked to
a confirmed or probable case
is a laboratory confirmed case of
Acute mumps infection can be confirmed by the presence
of serum mumps immunoglobulin M (IgM), a four-fold rise
in serum mumps immunoglobulin G (IgG) titer between acute
and convalescent phase serum specimens, positive mumps virus
culture, or detection of viral RNA by reverse transcription-polymerase
chain reaction (RT- PCR).
Laboratory criteria for diagnosis
- positive serologic test for serum
mumps IgM antibody, OR
- four-fold rise between acute- and
convalescent-phase titers in serum
mumps IgG antibody level by any standard
serologic assay, OR
- isolation of mumps virus from clinical
- detection of viral RNA by reverse
transcription polymerase chain reaction
The interpretation of a positive RT-
PCR result without demonstration of
mumps growth in tissue culture must
be interpreted carefully, particularly
among persons whose symptoms do not
meet the clinical definition of mumps.
What laboratory tests are conducted for mumps and what do they mean?
Mumps is confirmed using mumps IgM
antibody testing of serum samples
collected as soon as possible after
symptom onset for IgM testing. A positive
IgM test result indicates current/very
recent infection or reinfection. As
with any lab test, there can be false
positive test results. If the suspected
case has received one or more doses
of MMR, the IgM response may be missing,
delayed, or transient. If the acute
IgM is negative, a second serum
specimen should be collected. This
second specimen should be tested
for IgM as a delayed IgM response
has been reported to have occurred
in mumps cases during the recent
UK outbreak, and CDC has observed
a similar phenomenon during the
2006 outbreak. UPDATED Jan 5
IgG alone is not diagnostic unless
you obtain both an acute (can be
done as soon after onset as the
patient is seen, but ideally four
to five days after onset of symptoms)
and convalescent (from two to three
weeks after onset) blood specimen
for serologic tests to determine if
a four-fold rise in IgG antibody titer
has occurred (e.g., from 1:40 to 1:320).
increase in IgG titer as measured
in plaque-reduction neutralization
assays or similar quantitative
assays, or a seroconversion from
negative to positive in EIA assays
from acute to convalescent is considered
a positive diagnostic result for
vaccinated persons, the existing IgG
will begin to rise soon after exposure
and infection. At the time of onset
of symptoms and collection of the
acute serum, the IgG may already be
quite elevated, which would obviate
the 4-fold rise in titer expected
when comparing acute and convalescent
on Lab Testing for Mumps Infection
detection (Direct RT-PCR or virus
isolation with sequence analysis)
viral RNA may be detected from viral
samples prior to onset of parotitis
until 5-9 days after parotitis (1-4
days is optimal for virus collection).
Among previously immunized suspected
cases, mumps virus detection is
an important method of confirming
analysis of a RT-PCR product derived
from a virus isolate or from clinical
material confirms the presumptive
positive PCR results and provides
epidemiologically important information.
specimens should be collected?
highly recommend both the collection of
serum samples and a mumps viral specimen
(buccal swab) on each person with
suspected mumps as close to symptom onset
the mumps viral specimen a parotid
gland/buccal swab is the preferred
How should specimens be collected and managed?
testing: Collect 7-10 ml of blood
in a red top or serum separator
tube (SST). Store and ship specimens
cold (using ice packs).
serum: collect within
5 days after symptom onset
(at time of diagnosis) UPDATED
serum: collect within
weeks after symptom
- Mumps viral samples: Collect buccal
swab or throat swab as soon as mumps
is suspected. Samples may be positive
in unvaccinated persons out to 9 days
post onset, however among suspected
cases that have received 1 or more
doses of MMR, virus may be cleared
much earlier. A commercial product
designed for collection of throat
cultures or a plain Dacron swab can be used for the collection
of the buccal swab or throat swab (see information below regarding addition of fluids to keep swab moist).
* Synthetic swabs are preferred over cotton swabs which may contain substances that are inhibitory to enzymes used in RT-PCR.
UPDATED Jan 5
Gland/Buccal swab (.pdf):
may provide the best viral
sample. Massage the
parotid gland area
(the space between the
cheek and teeth just
below the ear) for
about 30 seconds prior
to collection of the
The parotid duct (Stensen’s
duct) drains in this space
near the upper rear molars.
A throat swab (oropharyngeal
or nasopharyngeal swab)
can also be collected
and added together with
the buccal swab.
swab in a tube containing 2-3
mls of viral transport medium
or cell culture medium (MEM
or Hanks Balanced Salt Solution)
or other sterile isotonic solution
(phosphate buffered saline). The presence of protein, for example 1 percent bovine albumin, 0.5 percent gelatin, or 2 percent serum, stabilizes the virus which otherwise loses 90-99 percent infectivity within 2 hours at 4C in a protein-free medium. UPDATED Jan 5
samples cold (4C). If there is
more than 1 day delay in shipping
the samples to the state lab or
CDC for testing, the buccal swab
or throat swab is best preserved
at -70C. Ship the viral
specimens using ice packs or dry
ice*. Avoid freeze-thaw cycles.
shipment contains both serum and
viral samples, ship together by
overnight service on cold packs
(do not freeze serum).
Where do I send the laboratory specimens for testing?
health department to determine
where to submit specimens and how
to ship them.
send specimens to CDC use
form 50.34 (see clarification note
For the onset date [top of CDC-50.34 (FRONT)],
please provide the onset date of parotitis or jaw swelling.
State Health Dept Laboratory
Address [top of CDC-50.34
(FRONT)], please also
provide a contact name with
telephone number or email
important information to
include: Type of
viral specimen and date
collected, serum date, MMR
vaccination history [date(s)
if known], clinical signs
and symptoms, patient date
of birth or age, and onset
date of parotitis or jaw
State Health departments and Public Health Labs may forward specimens for confirmatory testing.
Centers for Disease Control and Prevention
DASH / Unit 81
Attn: Dr. William J. Bellini
1600 Clifton Road
Call Jennifer Rota at 404-639-1156 or e-mail at firstname.lastname@example.org for additional information and to provide the details of the shipment.
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