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HelpTest Code LMALP Malaria PCR with Parasitemia Reflex, Varies
Useful For
Detection of Plasmodium DNA and identification of the infecting species, with reflex percent parasitemia calculated using thin blood films for positive cases
An adjunct to conventional microscopy of Giemsa-stained films
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
If positive, the percent parasitemia will be performed at an additional charge.
For more information see Malaria Laboratory Testing Algorithm.
Reporting Name
Malaria PCR with Parasitemia ReflexSpecimen Type
VariesOrdering Guidance
1. When monitoring percent parasitemia for patient response to therapy, order MAL / Rapid Malaria/Babesia Smear, Varies (conventional blood film exam) instead of this test.
2. This test is not performed on a STAT basis and, therefore, should not be used as a primary screening test for malaria.
3. This test is used primarily to confirm a presumptive malaria diagnosis and to determine infecting Plasmodium species, particularly when the parasite morphology on traditional blood films is suboptimal.
4. 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.
5. 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.
Shipping Instructions
Label all slides and place dry slides in a labeled slide box. Rubber band labeled slide box and labeled EDTA tube together and send to lab refrigerate.
Specimen Required
Both blood specimens and slides are required.
Specimen Type: Blood
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood 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. Blood films should be made from fresh blood using fingerstick or drops of blood from needle following venipuncture. 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 |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
Reference Values
Negative
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 and 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 determine species by morphology, and 1 mixed infection of P vivax/falciparum). The sensitivity and specificity of the real-time Plasmodium assay compared to microscopy and 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. Percent parasitemia will also be calculated using microscopic examination of blood smears.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 to 3 daysSpecimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
87798
87207 (if applicable)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| LMALP | Malaria PCR with Parasitemia Reflex | 47260-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 37116 | Malaria PCR w/ Parasitemia | 47260-5 |
Special Instructions
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MALCT | Plasmodium Percent Parasitemia Rflx | No | No |