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Order Code LCMAL Malaria, Molecular Detection, PCR, Varies

Reporting Name

Malaria PCR

Useful For

Detection of Plasmodium DNA and identification of the infecting species

 

An adjunct to conventional microscopy of Giemsa-stained films, particularly in cases of low percent parasitemia or suboptimal parasite morphology

 

Detection and confirmatory identification of Plasmodium species: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium knowlesi

 

This test should not be used to screen asymptomatic patients.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Varies


Ordering Guidance


1. This test is not performed on a STAT basis and, therefore, should not be used as a primary screening test for malaria.

2. This test is used primarily for confirmation of a presumptive malaria diagnosis and determination of infecting Plasmodium species-particularly when the parasite morphology on traditional blood films is suboptimal.

3. Clients in the Rochester, MN area who are seeking a primary test for malaria and who can deliver the specimen within 4 hours of collection should order MAL / Rapid Malaria/Babesia Smear, Varies.

4. Laboratories that are unable to deliver a specimen within 4 hours of collection should perform an initial screen for malaria and other blood parasites in their laboratory prior to sending a specimen to Mayo Clinic Laboratories.

5. This test does not include blood smear examination/calculation of parasitemia. If calculation of percent parasitemia is also desired for cases that are positive for Plasmodium species, clients should order LMALP / Malaria PCR with Parasitemia Reflex, Varies.



Specimen Required


Both blood specimens and slides are required.

 

Specimen Type: Blood

Container/Tube: Lavender top (EDTA)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube. Do not aliquot.

 

Specimen Type: Blood films

Container/Tube: Clean, grease-free slides in plastic slide container

Specimen Volume: 2 thin blood films and 2 thick blood films

Collection Instructions:

1. Ideally, blood films should be made directly from uncoagulated blood acquired via fingerstick. However, EDTA anticoagulated blood is also acceptable.

2. Prepare thin blood films as follows:

a. Prepare a thin film with a "feathered edge" that is no more than a single cell thick.

b. Allow the film to thoroughly air dry and then fix by briefly immersing in either absolute or 95% methyl alcohol.

c. Allow to air dry after fixation.

3. Prepare thick blood films as follows:

a. Place a large drop of blood (approximately the size of a dime and preferably from a fingerstick) on a slide.

b. Using a corner of a second slide, spread the drop in a circular motion while applying firm pressure to literally scratch the blood onto the carrier slide. This technique allows the blood to dry quickly and adhere well to the slide. Use approximately 20 circular sweeps with the second slide. The drop of blood should be about the size of a quarter when finished.

c. Do not fix. Air dry thoroughly (approximately 45 minutes) before placing in transport container.


Specimen Minimum Volume

Blood: 1 mL
Slides: See Specimen Required.

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Refrigerated (preferred) 7 days
  Ambient  7 days

Reference Values

Negative

Day(s) Performed

Monday through Sunday

CPT Code Information

87798

Method Description

DNA from EDTA-anticoagulated whole blood is extracted and tested using real-time polymerase chain reaction on the LightCycler 2.0 instrument (Roche Applied Science) with primers and fluorescence resonance energy transfer (FRET) probes. A genus-specific primer set corresponding to 18S ribosomal RNA is used to amplify target sequence. One pair of FRET hybridization probes was designed for Plasmodium falciparum over a region containing base pair mismatches allowing for differentiation of other Plasmodium species by use of melting curve analysis, while a second probe set is specific for Plasmodium knowlesi.(Babady NE, Sloan LM, Rosenblatt JE, Pritt BS: Detection of Plasmodium knowlesi by real-time polymerase chain reaction. Am J Trop Med Hyg. 2009 Sept;81(3):516-518)

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject

Method Name

Real-Time Polymerase Chain Reaction (PCR)/DNA Probe Hybridization

Testing Algorithm

For more information see Malaria Laboratory Testing Algorithm.

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.