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Leptospira serology (IgM antibody detection)

Published: August 9, 2026Updated: August 16, 2026

This test checks for antibodies to *Leptospira*, a bacterium that can cause illness after exposure to contaminated water or soil.

Quick summary

["Detects early infection from a tickborne or environmental exposure."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
6455-0
Short code
Leptospira Ur Cult
Synonyms
Leptospira Ur Cult
Category
coagulation
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
CPT
85610
SNOMED
396252006
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What This Test Measures

The test looks for IgM antibodies, a type of immune protein produced early in an infection. These antibodies appear within days to weeks after exposure and can help identify if you’ve recently been infected with *Leptospira*.

Why It’s Done

Doctors may order this test if you’ve had symptoms like fever, muscle aches, or fatigue after potential exposure to contaminated water, soil, or animal contact (e.g., farmworkers, travelers to endemic regions).

How the Test Works

Blood is drawn and tested for IgM antibodies using an immunoassay method. This identifies if your immune system has responded to the bacterium, which may indicate recent infection.

What to Expect

No special preparation is needed. A small blood sample is taken from your arm. Results may take a few days to a week to process.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: urine

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Leptospira IgM Antibody

Frequently asked questions

When might I get false-positive or negative results?
False positives can happen if you have other infections or if antibodies linger from past exposure. False negatives may occur if tested too early (before antibody production). Follow-up testing may be needed if initial results are unclear.
How long do results take?
Results are typically available within 1–7 business days, depending on lab processing times. Your doctor will discuss them with you.
Can I take antibiotics before testing?
No, antibiotics may affect results. If you’ve been prescribed them for suspected *Leptospira* infection, tell your doctor before testing.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy