Contrary to its name, blood poisoning does not involve poison. It refers to bacteria in the blood related to an infection. This bacteria is known as bacteremia. It does not always result in an infection, but when it does, it can be life-threatening.

Blood poisoning is not a medical term, but can refer to septicemia or sepsis. Septicemia is a bacterial infection in the blood. Sepsis is the body-wide inflammatory response to that infection, which can lead to organ failure or death.

Focusing on sepsis, this article discusses blood poisoning symptoms, diagnosis, and treatment.

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Symptoms of sepsis include the following:

  • Fever or chills
  • Sweating
  • Pain or discomfort
  • Increased heart rate
  • Confusion
  • Rapid breathing
  • Lightheadedness or dizziness

Signs of infection elsewhere in the body may be present. These include:

  • Skin wounds
  • Frequency or pain with urination
  • Cough
  • Diarrhea or vomiting

Warning Signs

Septic shock is a condition in which sepsis becomes very severe and causes low blood pressure. It is a medical emergency and typically requires treatment in an intensive care unit.

Signs of severe sepsis and septic shock include the following:

  • Low blood pressure
  • Elevated heart rate
  • Rapid breathing
  • Lightheadedness or dizziness
  • Loss of consciousness

Other signs include abnormal laboratory counts:

  • White blood cell count (blood oxygenation)
  • Abnormal kidney function
  • C-reactive protein (found in blood plasma)
  • Elevated lactate
  • Elevated procalcitonin

Causes and Risk Factors

Bacteria from untreated infections in the body can enter the blood and cause an inflammatory response. The body's immune system is programmed to respond to infection, but it can be overwhelmed by sepsis.

The most common infections that can lead to sepsis include:

The following may put a person at a higher risk of developing sepsis and poorer outcomes:

  • Being immunocompromised or on immunosuppressant medications
  • Having kidney disease, diabetes, or cancer
  • Children younger than 1 year
  • Age 65 or older
  • Previous hospitalization for an infection

How Is Blood Poisoning Diagnosed?

Blood poisoning can refer to either bacteremia or sepsis, and each of these has specific criteria for diagnosis.


Bacteremia is diagnosed with blood cultures. Blood cultures are a laboratory test used to diagnose bacteria in the blood.

  1. Four tubes of blood are taken from two separate sites, such as left arm and right arm. Two separate sites are needed because, in the process of a blood draw, the tube may be inadvertently contaminated with normal skin bacteria, which can make the results indeterminate.
  2. From each site, blood is drawn into an anaerobic and an aerobic tube. Certain bacteria can only grow in an aerobic tube, while others may prefer an anaerobic environment.
  3. The tubes are then brought to the laboratory where they are kept in a special temperature-controlled environment for at least five days to look for bacteria.
  4. If bacteria are found, testing can be performed to determine which antibiotics will work.


Sepsis diagnosis has changed over the years.

Special clinical scores such as the SOFA score or the qSOFA score can be used to determine organ dysfunction. These take into account physical examination findings and lab results including respiratory rate, oxygen levels, blood pressure, level of confusion, and kidney function.

How Is Sepsis Treated?

Treatment of bacteremia and sepsis involve treating the infection itself and providing supportive care.

Infection Treatment

Strong antibiotics are prescribed for sepsis in order to broadly cover potential bacteria. Once the laboratory has determined which antibiotics will be effective (called susceptibility testing), antibiotics can be narrowed to specifically target the bacteria.

Antibiotics may be required for up to a few weeks depending on the infection.

Sometimes, definitive treatment of the infection can require procedures or surgery. For example:

Supportive Care

Supportive care is essential in treating sepsis. Depending on the severity and needs, care may be provided in the intensive care unit with close monitoring.

Supportive care involves:

  • Hydration, often with intravenous fluids
  • Intubation and mechanical ventilation with a breathing tube when the body cannot handle the oxygen demands during sepsis
  • Pressors (intravenous medications that are used to increase a low blood pressure)
  • Dialysis may be needed for kidney failure (which may be temporary)

How Can I Prevent Blood Poisoning?

Early treatment of infection offers the best way to prevent sepsis from occurring, and early treatment of sepsis offers the best chances of recovery. People who are at higher risk of sepsis should pay close attention to any signs of infection.

Keeping chronic conditions like diabetes under control can also help prevent or reduce the severity of infections. Keeping vaccinations up to date is an important step to preventing certain viral and bacterial infections.

In addition, hygienic measures such as hand washing and preparing and handling food properly can help prevent infection.


Blood poisoning is a non-medical term used to describe an infection in the bloodstream, or sepsis. Sepsis is a medical emergency that requires hospitalization for treatment of infection.

Sepsis can result from lung, skin, gastrointestinal, or urological infections. It is more likely to occur in immunocompromised people, people with chronic health conditions, children under age 1, or adults age 65 and older.

Symptoms of sepsis include fever, chills, sweating, increased heart rate, shortness of breath, and confusion. Early treatment offers the best chances of recovery.

A Word From Verywell

If you think you have an infection, it's important to have it evaluated and treated promptly so that it doesn't spread or lead to sepsis. Some people are at higher risk of infection or may have a harder time fighting off infections. Early and fast treatment is essential, so seek medical attention right away if you experience symptoms.

Frequently Asked Questions

  • What does blood poisoning look like?

    Blood poisoning refers to sepsis, a condition in which an infection leads to a life-threatening inflammatory response. Symptoms include fever, high heart rate, low blood pressure, and confusion. Depending on the source of infection, diarrhea, cough, urinary symptoms, or skin infection may be present.

  • What type of bacteria can cause blood poisoning?

    Common causes of blood poisoning include Staphylococcus, Streptococcus, Escherichia coli, and Pneumococcal. Drug-resistant organisms that are resistant to certain antibiotics, such as Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant Enterococci, can also cause sepsis.

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