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Test ID: Fever and Rach PCR (Measles)
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Measles PCR
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Useful For
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In vitro test for the qualitative detection of viral nucleic acid as an aid to the evaluation of infections with Measles
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Method name and description
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Commercial multiplex real-time PCR technology for the nucleic acid detection of Measles virus.
Extracted RNA of Measles virus is transcribed into cDNA using a specific primer mediated reverse transcription step followed immediately in the same tube by polymerase chain reaction. The presence of specific viral sequences in the reaction is detected by an increase in the fluorescence observed from the relevant dual-labelled probe and is reported as a cycle threshold value (Ct) by the real time thermocycler. The assay uses bromo mosaic virus (BMV) as an internal control (IC), which is introduced into the lysis buffer at the extraction stage of each sample and control (Manufacturer package insert)
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Clinical information
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Measles is a highly contagious viral disease. It remains an important cause of death among young children globally, despite the availability of a safe and effective vaccine. Initial symptoms, which usually appear 10–12 days after infection, include high fever, a runny nose, bloodshot eyes, and tiny white spots on the inside of the mouth. Several days later, a rash develops, starting on the face and upper neck and gradually spreading downwards. Serious complications are more common in children under the age of 5, or adults over the age of 30. The most serious complications include blindness, encephalitis, severe diarrhoea and related dehydration, ear infections, or severe respiratory infections such as pneumonia.
https://www.who.int/immunization/diseases/measles/en/
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Aliases
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Measles RNA PCR
Measles RNA Qualitative PCR
Real time PCR for measles
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum, Plasma and body fluids
Specimen Volume: 2-3 mL
Specimen container/Tube:
- CSF (Plain sterile screw capped container,
- Whole blood in serum separator tube,
- Whole blood in EDTA tube,
- Throat swab in universal transport medium (UTM)
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Collection instructions / Special Precautions / Timing of collection
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Collection as per organization guidelines
No special precautions / Timing of collection
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Relevant clinical information to be provided
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Description of symptoms and history of the clinical presentation
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Storage and transport instructions
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The specimens should be transported immediately to Central Processing (CP) in the Qatar Rehabilitation Institute (QRI), 3rd floor, HBK MC in cool box with ice pack.
If blood specimen(s) cannot be delivered immediately to CP, store in a refrigerator (4 - 8◦C) for no more than 6 hours. Beyond that, separate plasma (centrifugation) and store at -70◦C
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Specimen Rejection Criteria
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- An inadequate volume of specimen for testing is received (QNS).
- The specimen has leaked
- Heparinized blood
- The specimen is in a wrong container
- Improper storage of specimen before submission to virology laboratory.
- Clots detected in plasma by receiving bench or by instruments
- Patient information on request does not match with information on the sample tube/container.
- There is gross hemolysis in plasma sample
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Biological reference intervals and clinical decision values
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- A positive result indicates the presence of specific Measles RNA and supports the diagnosis of Measles infection.
- A negative result indicates that the Measles virus RNA is undetectable in the sample but it does not exclude the presence of the virus or of an active/recent infection
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround time: within 7 days.
Test performed on Sunday-Thursday 7:00am-3:00PM
Specimen retention time: 1 month
CSF samples will be tested daily during the week and within 24 – 48 hours in the weekend.
Where a test result is deemed essential a STAT test can be arranged through the medical on-call rota
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