Understanding procalcitonin results

Overview

Procalcitonin is a protein your body makes when you have a serious bacterial infection. A simple blood test measures its level to help doctors tell bacterial infections from viral ones. This helps them decide whether to use antibiotics.

Procalcitonin testing is becoming more common, especially to guide antibiotic treatment in hospitals.

The test is used for people of any age who have symptoms of infection, such as fever, chills, rapid breathing, or confusion. It is particularly helpful when doctors suspect sepsis.

Symptoms

Common symptoms

• High fever or chills
• Rapid breathing or fast heart rate
• Confusion or disorientation
• Feeling very unwell or weak

Symptoms in children

• Fever (especially high or lasting)
• Unusual sleepiness or irritability
• Poor feeding or dehydration
• Rapid breathing or grunting

Symptoms in older adults

• Confusion or sudden change in mental state
• Low blood pressure or dizziness
• Fever or low body temperature
• Increased weakness or loss of appetite

Causes

Main causes

• Serious bacterial infections (such as pneumonia, meningitis, or bloodstream infection)
• Sepsis (a life-threatening response to infection)
• Major surgery, severe burns, or serious injury
• Severe inflammation not caused by infection

Risk factors

• Weakened immune system (due to illness or medication)
• Chronic diseases like diabetes or kidney disease
• Recent hospitalization, surgery, or invasive procedures
• Age under 1 year or over 65 years

When to see a doctor

See a doctor urgently if:

• If you have a high fever together with confusion, difficulty breathing, or severe pain
• If you have signs of sepsis (extreme shivering, fast heartbeat, very unwell feeling)

Book a routine appointment if:

• If you have a fever that lasts more than a few days without other serious symptoms
• If you are being treated for an infection and want to discuss test results

Diagnosis

A blood sample is taken from a vein in your arm and sent to a laboratory. The lab measures the level of procalcitonin in your blood. Results usually come back within a few hours.

Tests that may be done

• Procalcitonin blood test
• Complete blood count (CBC)
• Blood cultures to identify the specific bacteria
• Other tests depending on suspected infection (e.g., chest X-ray or urine test)

What to expect at your appointment

A healthcare worker will draw blood from a vein. You may feel a brief prick and have a small bruise afterward. Your doctor will explain your results and what they mean for your treatment plan.

Treatment

Treatment is directed at the underlying infection, not the procalcitonin level itself. If procalcitonin is high (indicating a bacterial infection), antibiotics are often prescribed. If it is low, antibiotics may be avoided to prevent overuse.

Self-care at home

• Get plenty of rest and stay hydrated
• Take steps to reduce fever (such as using a damp cloth on your forehead)
• Follow your doctor’s advice on taking any prescribed medicines exactly as directed

Medical treatments

For bacterial infections, doctors prescribe antibiotics. The choice depends on the type of infection and your overall health. For severe infections, intravenous antibiotics given in hospital may be needed. Your doctor will adjust treatment as your procalcitonin level changes.

When is surgery considered?

Surgery may be needed to drain an abscess or remove infected tissue that does not respond to antibiotics.

Living with this condition

After a serious infection, recovery can take time. Rest as needed and gradually return to normal activities. Finish all antibiotics even if you feel better, and attend follow-up appointments.

Lifestyle tips

• Practice good hand washing to avoid new infections
• Keep up to date with recommended vaccinations
• Avoid smoking and excessive alcohol, as they can weaken your immune system

Diet and exercise

Eat a balanced diet with plenty of fruits, vegetables, and lean protein to support your immune system. Gentle exercise, like walking, can help you regain strength. Do not overexert yourself while recovering.

Mental health and emotional wellbeing

Serious infections can be stressful. It is normal to feel anxious, tired, or down. Talk to your healthcare team about how you are feeling. Support from family and friends can also help.

Prevention

Many infections can be prevented with good hygiene, vaccination, and appropriate wound care. Procalcitonin testing itself does not prevent infection, but it helps ensure antibiotics are used wisely.

Vaccines

Vaccines such as those for flu, pneumonia, and whooping cough reduce your risk of serious bacterial infections.

Screening programmes

There is no routine screening for procalcitonin. It is used as a diagnostic test when a serious infection is suspected.

Complications

If left untreated

• Untreated bacterial infections can lead to sepsis, a life-threatening condition
• Organ failure (such as kidney or lung failure)
• Prolonged illness and longer hospital stays

Long-term outlook

With early detection and proper treatment, most bacterial infections improve. Procalcitonin levels fall as the infection clears. Your doctor will monitor your progress and adjust treatment as needed. Most people make a full recovery.

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