(eSwab or cup without preservatives)
Nasopharyngeal Swab
Specifications After Draw
Labeling: Label all containers with at least two patient identifiers (e.g., full name, date of birth), the date and time of collection, and the specimen type. This information must match the submission form.
Storage and Transport (RT-PCR specimens):
*Keep specimens cold (2-8°C, refrigerated) immediately after collection.
*If transport to the lab is within 48-72 hours, ship on frozen cold packs.
*If storage or transport is longer than 72 hours, freeze at -20°C or colder (ideally -70°C) and ship on dry ice.
*Avoid freeze-thaw cycles.
Storage and Transport (Serology specimens):
*Centrifuge blood collection tubes within 2 hours of collection to separate serum from the clot.
*Transfer the serum to a sterile, labeled transport tube.
*Refrigerate the serum (2-8°C).
*Ship refrigerated (on cold packs) if transport is within 7 days. For longer storage, freeze at -20°C or colder and ship on dry ice.
*Do not freeze whole blood.
REFRIGERATED\
Mon-Sat
Next Day
qPCR
Molecular
(RML)
Test
Interference and Rejection Criteria
Improper Collection/Handling: Poorly collected or handled specimens can lead to false-negative results.
Incorrect Swab Type:
*Use only sterile Dacron, Nylon, or flocked swabs with plastic shafts.
*Do not use calcium alginate, cotton-tipped, or wooden-shafted swabs, as these contain PCR inhibitors.
Incorrect Transport Media: Swabs must be in VTM or UTM. Dry swabs or swabs in bacterial transport media are generally not acceptable.
Timing of Collection:
*RT-PCR sensitivity is highest within the first 3-5 days after rash onset (up to a maximum of 10 days).
*Measles IgM antibodies may not be detectable until at least 72 hours (3 days) after rash onset, so a negative result before this time may require re-testing.
Vaccination Status: Recent MMR vaccination (within 6-45 days) can cause false-positive IgM results and interfere with distinguishing wild-type infection from vaccine response via serology alone; viral genotyping via PCR is needed in these cases.
Patient Conditions: The presence of rheumatoid factor or other rash illnesses (e.g., parvovirus B19) can cause false-positive IgM results.
Shipping Issues: Specimens received at ambient temperature (if required to be cold/frozen), grossly leaking, or without matching identifiers on the sample and form will be rejected.
Freeze-Thaw Cycles: Repeated freezing and thawing can compromise the integrity of specimens and should be avoided.
Miscellaneous Instructions to Collector
Collect Early: Collect all specimens as soon as possible after rash onset for optimal results, ideally at the first contact with the patient.
Simultaneous Collection: Collect both PCR and serology specimens at the same time.
Public Health Notification: Suspected measles cases are immediately notifiable. Contact your local or state health department/epidemiologist immediately to report the case and coordinate testing approval and shipping.
Universal Precautions: Follow standard universal precautions when collecting and handling all specimens (wear gloves, safety glasses, etc.).
Documentation: A completed laboratory requisition form must accompany the specimens, with complete clinical history, date of onset, and vaccination history.
Packaging: Place specimens in sealed, leak-proof biohazard bags with an absorbent pad. Place the requisition form in a separate outer pocket of the bag (never in the same compartment as the specimen) in case of leakage.
Isolation: The patient should be isolated until measles is ruled out, and the exam room should remain closed for at least 2 hours after the patient has left.
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