Test Catalog

Test Id : LBAB

Babesia species, Molecular Detection, PCR, Blood

Useful For
Suggests clinical disorders or settings where the test may be helpful

An initial screening or confirmatory testing method 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.

Method Name
A short description of the method used to perform the test

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

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Babesia species, PCR, B

Aliases
Lists additional common names for a test, as an aid in searching

Babesiosis, PCR

PCR (Polymerase Chain Reaction)

PCR, Babesia microti

PCR, Babesia duncani

PCR, Babesia divergens

PCR, Babesia MO-1

Babesia microti

Specimen Type
Describes the specimen type validated for testing

Whole Blood EDTA

Ordering Guidance

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

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Container/Tube: Lavender top (EDTA)

Specimen Volume: 1 mL

Forms

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

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Hemolysis Mild OK; Gross OK
Lipemia Mild OK; Gross reject
Icterus NA
Other Green-top (heparin) tube

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

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

Useful For
Suggests clinical disorders or settings where the test may be helpful

An initial screening or confirmatory testing method 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.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Babesiosis is a tick-transmitted zoonosis caused by intraerythrocytic protozoa in the genus Babesia. Babesia microti is responsible for the vast majority of human cases in the United States, with most cases occurring along the Northeast Coast and the upper Midwestern states. A small number of cases of B duncani human infection have also been reported along Pacific Coast states from Washington to northern California, and B divergens/B divergens-like strains have been detected in humans in Missouri (MO-1 strain), Kentucky, and Washington. In Europe, B divergens and B venatorum are the primary causes of human babesiosis.

 

Humans most commonly acquire infection through the bite of an infected tick. The most common tick vectors in the United States are Ixodes scapularis and Ixodes pacificus, while Ixodes ricinus and other ticks transmit the parasite in Europe and Asia. Less commonly, babesiosis may be acquired through blood transfusion and across the placenta from the mother to the fetus.

 

Most patients with babesiosis are asymptomatic or have only a self-limited mild flu-like illness, but some develop a severe illness that may result in death. Patient symptoms may include fever, chills, extreme fatigue, and severe anemia. The most severe cases occur in asplenic individuals and those over 50 years of age. Rare cases of chronic parasitemia, usually in immunocompromised patients, have been described.

 

Babesiosis is conventionally diagnosed through microscopic examination of Giemsa-stained thick and thin peripheral blood films looking for characteristic intraerythrocytic Babesia parasites. This method is relatively rapid, widely available, and capable of detecting (but not differentiating) human-infective Babesia species. It is also necessary for calculating the percentage of parasitemia which is used to predict prognosis, guide patient management, and monitor response to treatment. However, microscopic examination requires skilled microscopists and may be challenging in the setting of low parasitemia or prior drug therapy. Also, Babesia species may closely resemble those of Plasmodium falciparum.

 

The Mayo Clinic real-time PCR assay provides a rapid and more sensitive alternative to blood film examination for detection and differentiation of B microti, B duncani, and B divergens/B divergens-like parasites. It does not cross-react with malaria parasites.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Negative

Interpretation
Provides information to assist in interpretation of the test results

A positive result indicates the presence of Babesia species DNA and is consistent with active or recent infection. While positive results are highly specific indicators of disease, they should be correlated with blood smear microscopy, serological results and clinical findings.

 

A negative result indicates absence of detectable DNA from Babesia species in the specimen, but does not always rule out ongoing babesiosis in a seropositive person, since the parasitemia may be present at a very low level or may be sporadic.

 

Other tests to consider in the evaluation of a patient presenting with an acute febrile illness following tick exposure include serologic tests for Lyme disease (Borrelia burgdorferi), and molecular detection (PCR) for ehrlichiosis/anaplasmosis. For patients who are past the acute stage of infection, serologic tests for these organisms should be ordered prior to PCR testing.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

While this assay is designed to detect symptomatic infection with Babesia microti, B duncani, and B divergens/MO-1, it may detect low-grade asymptomatic parasitemia in individuals in babesiosis-endemic areas. Thus, it should only be used for testing patients with a clinical history and symptoms consistent with babesiosis.

 

Inhibitory substances may cause false-negative results.

 

Inadequate specimen collection or improper storage may invalidate test results.

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 PCR assay and another real-time PCR assay. Concordance was 99%.

 

Analytical Sensitivity/Limit of Detection (LoD). The LoD established using whole organism spiked into specimen matrix (whole blood) is as follows:

-Babesia microti, ATCC PRA 99 -                        2,670 target copies/mL

-B duncani ATCC PRA 302         -           1,540 target copies/mL

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

-B divergens positive patient DNA -        5,270 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 Babesia species PCR. The PCR was able to consistently detect 2 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).

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Anderson JF, Mintz ED, Gadbaw JJ, et al: Babesia microti, human babesiosis and Borrelia burgdorferi in Connecticut. J Clin Microbiol 1991;29(12):2779-2783

2. Herwaldt BL, de Bruyn G, Pieniazek NJ, et al: Babesia divergens-like infection, Washington State. Emerg Infect Dis 2004;10(4):622-629

3. Herwaldt B, Persing DH, Precigout EA, et al: A fatal case of babesiosis in Missouri: identification of another piroplasm that infects humans. Ann Intern Med 1996;124(7):643-650

4. Persing DH, Herwaldt BL, Glaser C, et al: Infection with a Babesia-like organism in northern California. N Engl J Med 1995;332(5):298-303

5. Quick RE, Herwaldt BL, Thomford JW, et al: Babesiosis in Washington State: a new species of Babesia? Ann Intern Med 1993;119(4):284-290

6. Vannier E, Krause PJ: Human Babesiosis. N Engl J Med 2012 Jun 21;366(25):2397-2407

7. Burgess MJ, Rosenbaum ER, Pritt BS, et al. Possible Transfusion-Transmitted Babesia divergens-like/MO-1 in an Arkansas Patient. Clin Infect Dis 2017

Method Description
Describes how the test is performed and provides a method-specific reference

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 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, which 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 (FRET) 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 in an Arkansas Patient. Clin Infect Dis 2017; Supplemental Data)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Saturday; Varies

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 day - 4 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

1 week

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

87798 x 3

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports