Among 275,020 (87%) specimens tested for measles immunoglobulin
M, 78,950 (29%) were positive; 203,898 (64%) also were tested for rubella immunoglobulin M, and 11,874 (6%) were positive.
The samples were examined for measles immunoglobulin
G with the qualitative micro-ELISA kit (NovaTec Immundiagnostica GmbH, Dietzenbach, Germany).
In our case, both measles immunoglobulin
(Ig)-M and IgG were positive.
The criteria for the laboratory diagnosis included the presence of measles immunoglobulin
(Ig) M, isolation of measles virus, or identification of measles virus by reverse transcription PCR (2,3).
** Discarded nonmeasles cases include those suspected measles cases with an adequate specimen for laboratory testing that were found to be measles immunoglobulin
M (IgM) antibody negative or rubella IgM antibody positive.
Of the serum samples tested, 1,053 (15%) of 6,999 were positive for measles immunoglobulin
(Ig) M; most were collected during 2006 (Figure 1).
Confirmed measles was defined as positive test for measles by urine PCR or positive/equivocal measles immunoglobulin
M, and a probable case was defined as a suspected case with suggestive laboratory results (positive immunoglobulin G [IgG] with high IgG avidity, indicative of a past immunologic response to measles vaccine or infection).
Measles diagnosis was confirmed in the patient on July 16 by detection of measles virus by real-time polymerase chain reaction (PCR) from a nasopharyngeal swab specimen collected early on July 15; a positive measles immunoglobulin
M (IgM) antibody titer was reported on July 20.
A confirmed case is an acute febrile rash illness with isolation of measles virus from a clinical specimen; or detection of measles-virus specific nucleic acid from a clinical specimen using polymerase chain reaction; or immunoglobulin G seroconversion or a significant rise in measles immunoglobulin
G antibody using an evaluated and validated method; or a positive serologic test for measles immunoglobulin
M antibody; or direct epidemiologic linkage to a case confirmed by one of these methods.
On April 15, 2016, local public health officials in Shelby County, Tennessee, were notified of a positive measles immunoglobulin
M (IgM) test for a male aged 18 months (patient A).
According to JRF data, the number of specimens tested annually for measles immunoglobulin
M (IgM) increased 51% during 2010-2014, from 171,170 to 258,339.
Testing for measles immunoglobulin
G (IgG) and immunoglobulin M (IgM) and testing for measles virus RNA by reverse-transcription polymerase chain reaction (RT-PCR) were performed, and measles genotype was determined.