Leptospira Antibody, IgM by Dot Blot
Ordering Recommendation

Aids in the detection of acute leptospirosis.

Qualitative Immunoblot
Mon, Thu
1-5 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Serum separator tube or green (sodium or lithium heparin). 
Specimen Preparation
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.05 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
Contaminated, heat-inactivated, hemolyzed, severely lipemic specimens. Any other body fluid. 
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid  repeated freeze/thaw cycles) 
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.

A negative result does not rule out the possibility of leptospirosis.
Hotline History
Component Test Code*Component Chart NameLOINC
0055233Leptospira IgM23202-5
* 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 view this test within the Laboratory Test Directory found at www.aruplab.com
  • Leptospira IgM antibody
  • Leptospira IgM Dot Blot