What is the blood test for Listeria?
John Peck
Updated on March 29, 2026
Although blood cultures are the standard for diagnosis in cases of fever and symptoms consistent with listeriosis, if an amniocentesis has been performed, it usually reveals meconium staining and gram-positive rods 17. This information may help guide management when the diagnosis is uncertain 18.
When does Listeria show in blood?
People with invasive listeriosis usually report symptoms starting 1 to 4 weeks after eating food contaminated with Listeria; some people have reported symptoms starting as late as 70 days after exposure or as early as the same day of exposure.
How do you get diagnosed with Listeria?
Listeriosis is usually diagnosed when a bacterial culture (a type of laboratory test) grows Listeria monocytogenes from a body tissue or fluid, such as blood, spinal fluid, or the placenta. Listeriosis is treated with antibiotics.
How do I know if I have listeriosis?
What are the symptoms of listeriosis? Listeriosis can cause mild, flu-like symptoms such as fever, chills, muscle aches, and diarrhea or upset stomach. You also may have a stiff neck, headache, confusion, or loss of balance. Symptoms may appear as late as 2 months after you have eaten something with Listeria.
Will Listeria show up in bloodwork?
A blood test is often the most effective way to determine whether you have a listeria infection. In some cases, samples of urine or spinal fluid will be tested as well.
What antibiotic treats Listeria?
Listeria infections are associated with a high mortality rate, and thus effective antibiotic treatment is essential. Although a variety of antibiotics have activity against the organism, ampicillin alone or in combination with gentamicin remains the treatment of choice.
Which antibiotics treat listeria?
How long does Listeria stay in your system?
Treatment and Medication Options for Listeria Infection Their immune system will eradicate the bacteria, and symptoms will tend to go away within three days, though they may last as long as one week.
Can you have listeria without fever?
If you are having mild symptoms, you should notify your health care provider, but if you do not have a fever, many experts feel it’s OK to watch and see if anything develops.
How do doctors treat Listeria infection?
In some cases, samples of urine or spinal fluid will be tested as well. Treatment of listeria infection varies, depending on the severity of the signs and symptoms. Most people with mild symptoms require no treatment. More-serious infections can be treated with antibiotics.
Can a blood test detect food poisoning?
Lab tests aren’t always needed for food poisoning, and don’t diagnose every case. Your doctor may order a blood test if they think the infection has spread into the blood. Blood tests can detect the bacteria Listeria monocytogenes and the hepatitis A virus. It also can check for toxins, such as for botulism, which can be deadly.
How do you treat Listeria?
Rest: Take it easy until your symptoms subside.