Ordering Recommendation

Aids in the detection of acute leptospirosis.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Serum Separator Tube (SST) or Green (Sodium or Lithium Heparin).

Specimen Preparation

Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.2 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Please mark specimen plainly as acute or convalescent.

Storage/Transport Temperature


Unacceptable Conditions

Any other body fluid. Contaminated, heat-inactivated, hemolyzed, severely lipemic specimens.


After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid  repeated freeze/thaw cycles)


Qualitative Immunoblot


Mon, Thu


1-5 days

Reference Interval

Negative: No significant level of Leptospira IgM antibody detected.
Equivocal: Questionable presence of Leptospira IgM antibody detected.  Repeat testing in 10-14 days may be helpful.
Positive: Presence of IgM antibody to Leptospira detected, suggestive of a current or recent infection.

Interpretive Data

Samples interpreted as negative indicate that antibody is not present in the sample, or is below the detection level of the method.  Since antibodies may not be present during early disease, confirmation two to three weeks later is recommended.  An initially-negative result followed by a positive result indicates IgM seroconversion.

Equivocal specimens should be cautiously interpreted.  Further testing with an additional specimen is recommended. If the specimen remains equivocal, a second serological method should be considered if leptospirosis infection is still suspected.

Samples interpreted as positive may indicate the specific antibody.  Antibody presence alone cannot be used for diagnosis of acute infection, however, because antibodies from prior exposure may circulate for a prolonged period of time.

Compliance Category



A negative result does not rule out the possibility of leptospirosis.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0055233 Leptospira IgM 23202-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Leptospira IgM antibody
  • Leptospira IgM Dot Blot
Leptospira Antibody, IgM by Dot Blot