Identifying measles virus infection using throat swab specimens
Real-Time Polymerase Chain Reaction (PCR)
MEASR
Measles virus
Measles
Rubeola
Varies
Polymerase chain reaction testing (this test) is recommended as the first-line test if a patient has symptoms of measles (ie, cough, fever, conjunctivitis, rash).
If serology has been performed and IgM-class antibodies against measles are detected (ROGM / Measles (Rubeola) Virus Antibody, IgM and IgG, Serum), this test should be ordered to confirm measles infection.
Specimens should be transported as soon as possible.
Specimen Type: Throat Swab
Supplies: Culturette (BBL Culture Swab) (T092)
Container/Tube: Sterile container with transport media
Specimen Volume: Entire collection
Collection Instructions:
1. Collect specimen by swabbing back and forth over mucosal surface to maximize recovery of cells.
2. Swab must be placed into viral transport media (eg, M4-RT, M4, M5, Bartels FlexTrans Transport Media, Jiangsu Transport Media)
0.3 mL
E-swab, calcium alginate-tipped swab, wood swab, dry swab, or transport swab containing gel or charcoal additive | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Refrigerated (preferred) | 7 days | |
Frozen | 7 days |
Identifying measles virus infection using throat swab specimens
Negative
A positive result indicates the presence of measles virus RNA in the specimen.
The potential for false-negative results exists due to improper sample collection or viral variants.
The following validation data support the use of this assay for clinical testing.
Accuracy:
Accuracy studies were performed by testing negative and positive (near the limit of detection) urine and upper respiratory swab samples. Urine yielded 88% positive agreement and 100% negative agreement with expected results. Upper respiratory swabs yielded 100% positive and 100% negative agreement with expected results.
Analytical Sensitivity/Limit of Detection:
The lower limit of detection of this assay is 2 genome copies/mcL for urine and 1 copy/mcL for throat swabs.
Precision:
Inter-assay and intra-assay precisions were 100%.
Specificity:
No sequences were identified that would result in cross-reactivity with the assay by in silico analysis. No cross-reactivity was detected in experiments testing a panel of nucleic acid extracts from greater than 50 bacterial, fungal, and viral organisms causing similar disease or commonly found in urine or throat swabs.
Reportable Range:
This is a qualitative assay, and the results are reported as either "negative" or "positive" for the measles virus target.
2. Moss WJ. Measles. Lancet. 2017 Dec;390(10111):2490-2502
3. Porter A, Goldfarb J. Measles: a dangerous vaccine-preventable disease returns. Cleve Clin J Med. 2019 Jun;86(6):393-398
This assay employs a reverse transcription reaction to convert RNA to complementary DNA. Oligonucleotide forward and reverse primers specific to the nucleoprotein (N) gene region of the measles virus amplify the target sequence. A TaqMan probe labeled with the fluorophore FAM and specific to the target region of measles virus RNA binds to amplified measles RNA virus product. Ribonuclease P (RNase P) is used as an internal control. Oligonucleotide forward and reverse primers specific to the p30 subunit of RNase P amplify the internal control target sequence. A TaqMan probe labeled with fluorophore Cy5 and specific to RNase P bind to the amplified RNase P product. The dye-labeled TaqMan probes allow for the detection of the target and internal control in the corresponding channels of the Roche LightCycler 480 II (LC480) instrument. Detection of the target N gene region indicates the presence of measles virus RNA in the specimen. The clinical validity of RT-PCR for the detection of the N gene of measles virus RNA in urine and throat swabs is well documented in peer-reviewed literature.(Unpublished Mayo method)
Monday through Friday
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
87798
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
MEASR | Measles Virus PCR, Throat | 91077-8 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
617821 | Measles Virus PCR, Throat | 91077-8 |
Change Type | Effective Date |
---|---|
New Test | 2022-12-13 |