Home
HelpTest Code LAB1231729 Malaria, Molecular Detection, PCR, Varies
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Malaria PCRSpecimen Type
VariesOrdering 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.
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Refrigerated (preferred) | 7 days | |
| Ambient | 7 days |
Specimen Minimum Volume
Blood: 1 mL
Slides: See Specimen Required.
Special Instructions
Day(s) Performed
Monday through Sunday
Specimen Retention Time
7 daysReport Available
Same day/1 to 3 daysReference Values
Negative
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.
Testing Algorithm
For more information see Malaria Laboratory Testing Algorithm.
CPT Code Information
87798
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| LCMAL | Malaria PCR | 47260-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 87860 | Malaria PCR | 47260-5 |
Supportive Data
The following supports the use of this assay for clinical testing.
Accuracy/Diagnostic Sensitivity and Specificity:
A total of 160 clinical whole blood specimens were evaluated for the presence of Plasmodium species DNA or the 18S ribosomal RNA gene using this real-time polymerase chain reaction (PCR) assay. The assay detects and differentiates DNA of Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium knowlesi. The results were compared to results of microscopy, a nested PCR method and sequencing. The specimens comprised 48 negative and 108 positive specimens (32 P falciparum, 8 P malariae, 20 P ovale, 45 P vivax, 2 unable to speciate by morphology, and 1 mixed infection of P vivax/falciparum). The sensitivity and specificity of the real-time Plasmodium assay compared to microscopy, nested PCR and sequencing was 99% and 94% respectively, with all species determinations by the PCR assay matching the original result. No P knowlesi clinical specimens were available, so spiking studies were performed. Thirty EDTA-anticoagulated blood specimens received in the laboratory for unrelated testing were spiked with P knowlesi plasmid near the limit of detection (50-100 targets per microliter) and tested in a blinded fashion with negative blood specimens. 100% concordance was achieved in the spiking studies.
Analytical Sensitivity/Limit of Detection:
The lower limit of detection of this assay is 10 to 50 DNA target copies per microliter in whole blood.
Analytical Specificity:
No PCR signal was obtained from extracts of 31 other bacterial, viral, rickettsial, and parasitic isolates that could be found in whole blood and cause similar symptoms, including Babesia, Borrelia, Anaplasma, and Ehrlichia species.
Precision:
Interassay precision was 100% and the intra-assay precision was 100%.
Reportable Range:
This is a qualitative assay, and the results are reported as either negative or positive for the targeted Plasmodium species.
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.