Diagnostic Tests for Babesia

BABESIA IFA

The Babesia immuno-fluorescence assay (IFA) is designed to detect human IgM and IgG antibodies to Babesia antigens in human serum. For diagnostic purposes, Babesia IFA test results should be used in conjunction with other information available to the physician. Currently we offer B. microti and B. duncani IFA tests.

Principal

The Babesia IFA assay is a “two-stage” sandwich assay, which is based upon an antigen-antibody complex formation in the following steps:

  1. Binding of anti-Babesia specific antibodies in human serum to fixed Babesia on a slide.
  2. Binding of fluorescent-labeled anti-human IgG/IgM antibodies specific to the human anti– Babesia antibodies bound to fixed Babesia on the slide. 
  3. Identifying green fluorescing Babesia parasites with a fluorescent microscope.

Result Interpretation

Reference Range

  • Babesia antibody titers IgM        <20
  • Babesia antibody titers IgG         <40

Clinical Significance

The Babesia immunofluorescent antibody test is used to detect antibodies to Babesia in human serum. Titers rise during the first 2 to 4 weeks of illness and decline over 6 to 12 months. In patients with previously high titers, an IgG titer of <160 may indicate a resolving infection. If the IFA is negative but clinical symptoms are present, PCR and/or FISH testing are suggested. Babesia is carried by the same ticks that have also been known to cause ehrlichiosis, bartonellosis, and Lyme disease. Patients with positive titers should also be tested for other tick-borne diseases.

Limitations

  1. A single negative IFA test result does not exclude the possibility of Babesia infection.
  2. Other Babesia spp. antibodies may cross-react and yield a false positive Babesia IFA test.
  3. Results should be interpreted in conjunction with other laboratory and clinical findings.

Ordering Information

  • Specimen Serum – minimum volume 0.5 ml
  • Container SST (Serum Separator Tube) OR Leak-proof tube
  • Collection and Shipping Instructions: See Serum and Whole Blood Samples- Collection & Shipping Instructions [This will link to this page]

Tests Offered

Test# 200 B. microti IgG & IgM Ab CPT Code 86317 x2
Test# 720 B. duncani IgG & IgM Ab** CPT Code 86317 x2
B. microti IgG & IgM Antibody and/or B. duncani IgG & IgM Antibody are part of the following Test Panels:
Test Panel# 8095 NN Co-infection Panel**
Test Panel# 5080 Western Regional Co-infection Panel**
Test Panel# 5085 New Western Regional Co-infection Panel**(includes Bartonella FISH)
Test Panel# 5090 Complete Co-infection Panel
Test Panel# 5095 New Complete Co-infection Panel (includes Bartonella FISH)
Test Panel# 670 Comprehensive Babesia Panel
Test Panel# 690 West Coast Babesia Panel**
Test Panel# 695 Complete Babesia Panel**
Test Panel# 5060 TBD Panel**

**Test/Panels are not yet available for New York Residents

BABESIOSIS PCR SCREEN (B. MICROTI AND/OR B. DUNCANI)

The Babesia microti/duncani PCR Screen is an assay that detects Babesia DNA in whole blood and speciates to B. microti and B. duncani. The combination of the following three steps imparts a very high specificity and sensitivity to the test.

  • Hybridization/Selection
  • Amplification of Babesia-specific DNA
  • Detection of Babesia-specific amplified DNA fragments

Result Interpretation

Reference Range

  • B. microti: Negative, B. microti specific DNA not detected
  • B. duncani:  Negative, B. duncani specific DNA not detected

Clinical Significance The Babesia microti/duncani PCR Screen is an assay that detects Babesia specific DNA (B. microti and/or B. duncani). Babesia rDNA fragments are hybrid-selected by probes, followed by PCR amplification of selected Babesia rDNA.  PCR products are confirmed with Babesia specific probes in a Southern Blot Assay.  The primers and probes used for the selection of Babesia rDNA fragments are designed from published small ribosomal RNA sequences.

Limitations

  1. Results should be interpreted in conjunction with other laboratory and clinical findings.
  2. Test results can only help the physician in confirming clinical diagnosis.

Ordering Information

  • Specimen Whole Blood – minimum volume 2 ml
  • Container SST (Serum Separator Tube) OR Leak-proof tube
  • Collection and Shipping Instructions: See Serum and Whole Blood Samples- Collection & Shipping Instructions[This will link to that page]

Test Offered

Test# 663 Babesia PCR Panel (B. microti and/or B. duncani) CPT Code 87797, 87798 x2
Babesia PCR Panel for B. microti and B. duncani is part of the following Test Panels:
Test Panel# 670 Comprehensive Babesia Panel
Test Panel# 690 West Coast Babesia Panel**
Test Panel# 695 Complete Babesia Panel**

**Test/Panels are not yet available for New York Residents

BABESIA FISH

The Fluorescent In-Situ Hybridization (FISH) assay is designed for qualitative detection of ribosomal RNA of Babesia parasites directly in a blood smear. The test’s highest degree of specificity is provided by nucleic acid probes, which bind to RNA sequences of the Babesia.  This test detects all species of Babesia.

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Principal

The FISH assay is based on two fundamental principles:

  1. Hybridization directly on a thin blood smear with a fluorescein-labeled Babesia –specific probe.
  2. Identification of Babesia parasites on a blood smear by viewing with a fluorescent microscope.

Result Interpretation

Reference Range

Babesia  Negative, Babesia specific rRNA not detected.

Clinical Significance

The Fluorescence In-Situ Hybridization test (FISH) provides a significant increase in sensitivity and specificity over standard Giemsa-stained smears for the presence of intraerythrocytic parasites (piroplasts) in RBCs. The parasites exist as a ring and/or merozoite forms. A positive sample must show fluorescing rings in at least 2 RBCs. A negative sample must show no fluorescence within the RBCs.

Limitations

  1. A single negative FISH test result does not exclude the possibility of Babesia infection.
  2. Results should be interpreted in conjunction with other laboratory and clinical findings.

Special Instructions

  1. In special circumstances, blood smears may be accepted by IGeneX for testing in place of EDTA whole blood. Please contact our Lab Director for more information and authorization. Smears made improperly will not be accepted.
  2. Medicare patients, download ABN forms here. [This will link to the forms page]

Ordering Information

  • Specimen Whole Blood – minimum volume 2 ml
  • Container SST (Serum Separator Tube) OR Leak-proof tubeCollection and Shipping Instructions: See Serum and Whole Blood Samples- Collection & Shipping Instructions [This will link to this page]

Test Offered

Test# 640 Babesia FISH (RNA) CPT Code 88365
Babesia FISH (RNA) is part of the following Test Panels:
Test Panel# 8095 NN Co-infection Panel**
Test Panel# 5080 Western Regional Co-infection Panel**
Test Panel# 5085 New Western Regional Co-infection Panel**(includes Bartonella FISH)
Test Panel# 5090 Complete Co-infection Panel
Test Panel# 5095 New Complete Co-infection Panel (includes Bartonella FISH)
Test Panel# 670 Comprehensive Babesia Panel
Test Panel# 690 West Coast Babesia Panel**
Test Panel# 695 Complete Babesia Panel**
Test Panel# 5060 TBD Panel**

**Test/Panels are not yet available for New York Residents