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Test Code LAB1235612 Babesia species, Molecular Detection, PCR, Blood


Ordering Guidance


This is a qualitative assay, and the results are reported either as negative or positive for targeted Babesia species DNA.



Specimen Required


Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Royal blue top (EDTA), pink top (EDTA), or sterile vial containing EDTA-derived aliquot

Specimen Volume: 1 mL

Collection Instructions: Send whole blood specimen in original tube (preferred).


Useful For

Initial screening or confirmatory testing for suspected babesiosis during the acute febrile stage of infection in patients from endemic areas, especially when Giemsa-stained peripheral blood smears do not reveal any organisms, or the organism morphology is inconclusive

Reporting Name

Babesia species PCR, B

Specimen Type

Whole Blood EDTA

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood EDTA Refrigerated (preferred) 7 days
  Frozen  7 days

Reject Due To

Gross hemolysis OK
Gross lipemia Reject

Reference Values

Negative

Reference values apply to all ages.

Supportive Data

The following validation data supports the use of this assay for clinical testing.

 

Accuracy/Diagnostic Sensitivity and Specificity:

Ninety-six whole blood specimens were tested by this real-time polymerase chain reaction (PCR) assay and another real-time PCR assay. Concordance was 99%.

 

Analytical Sensitivity/Limit of Detection:

The limit of detection established using whole organism spiked into specimen matrix (whole blood) is as follows:

-Babesia microti, ATCC PRA 99-2670 target copies/mL

-Babesia duncani ATCC PRA 302-1540 target copies/mL

-Babesia MO-1 positive patient DNA-10,700 target copies/mL

-Babesia divergens positive patient DNA-5270 target copies/mL

 

Serial 10-fold dilutions of microscopy-positive specimens were also tested in a blinded fashion using conventional thick and thin blood films and the Mayo Clinic Babesia species PCR test. The PCR test was able to consistently detect two 10-fold dilutions lower than using microscopy.

 

Analytical Specificity:

No cross-reactivity was noted using a panel of 34 bacteria, viruses, parasites, and fungi were detected by the Babesia species PCR.

 

Precision:

Interassay and intra-assay precision was 100% precision.

 

Reference Range:

The reference range is negative. This was confirmed by testing 93 blood specimens from asymptomatic individuals for the presence of Babesia species by the Babesia species PCR assay. All 93 specimens were negative.

 

Reportable Range:

This test is a qualitative assay, and results are reported as positive or negative for Babesia species (B microti, B duncani, B divergens, and Babesia MO-1).

Method Description

Nucleic acid is extracted from EDTA whole blood using the automated MagNA Pure bead-based system (Roche Molecular Systems). The extract is then transferred to individual self-contained capillary cuvettes for amplification. The LightCycler is an automated instrument that amplifies and monitors the development of target nucleic acid (amplicon) after each cycle of polymerase chain reaction (PCR).

 

The DNA target for PCR assay is a gene encoding the nuclear small subunit ribosomal RNA (SS-rDNA). This assay consists of 2 forward primers, 1 reverse primer, and 2 probes that are specific for the Babesia species target DNA. The specific base pair DNA target sequence is first amplified by PCR using the target-specific primers. Amplicon is then detected during melting curve analysis using fluorescence resonance energy transfer probes, which utilizes one hybridization probe with a donor fluorophore, fluorescein, at the 3' end and a second hybridization probe with an acceptor fluorophore, LC-Red 640, at the 5' end. Fluorescence is produced when the 2 probes anneal to the target sequence in close proximity to one another. The LC-Red 640 then emits a measurable and quantifiable light signal at a specific wavelength.(Burgess MJ, Rosenbaum ER, Pritt BS, et al. Possible transfusion-transmitted Babesia divergens-like/MO-1 infection in an Arkansas patient. Clin Infect Dis. 2017;64[11]:1622-1625)

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 to 4 days

Specimen Retention Time

1 week

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

87798 x2

87469

87999 (if appropriate for government payers)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BABPB Babesia species PCR, B 88461-9

 

Result ID Test Result Name Result LOINC Value
618317 Babesia microti 88452-8
618318 Babesia duncani 88451-0
618319 Babesia divergens/MO-1 88450-2

Forms

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