Procalcitonin Test: What It Is, Why It's Done, and What Your Results Mean

Just got back from a hospital, and your physician asked you to undergo what's known as a Procalcitonin test? Your sibling may have a high fever that won't abate, or you may be suffering from an infection and being monitored. Whichever the case, seeing a new term on the lab slip can make you wonder a lot. What is this test all about? Does it concern something grave? What implications does it hold for your overall well-being?

A procalcitonin test, abbreviated PCT, is a laboratory test used to diagnose bacterial infection and assess its severity. The test is especially valuable for detecting sepsis. This blog explains what the test measures, why it is recommended, normal ranges, high levels, and what your results may indicate.

What Is a Procalcitonin Test? Understanding the Basics

Procalcitonin is one type of hormone synthesized by the body's cells in cases of bacterial infection or severe tissue damage. Under normal, healthy conditions, procalcitonin levels are low in the blood. Still, during an acute bacterial infection, this hormone level increases sharply within the first few hours after infection onset.

The procalcitonin test is a method of detecting procalcitonin in the patient's blood. Since this hormone responds only to bacterial infections, the test results will help the doctor differentiate between bacterial and viral diseases. This information can be extremely important for choosing appropriate treatment.

Why Is the Procalcitonin Test Done?

PCT testing is recommended for various reasons. It is not a standard test performed in all cases of fever or even in all cases of infection. Rather, the test is usually performed when there is concern about something more serious occurring inside the body. 

Common reasons your doctor may order a PCT test include:

• Bacterial sepsis or a systemic bacterial infection suspicion
• Monitoring a patient already diagnosed with sepsis to track recovery
• Differentiation between bacterial and viral pneumonia
• Support of antibiotic treatment: when to begin, continue, or end the course of therapy
• Evaluating critical patients in ICU units
• Monitoring infections post-surgery

Additionally, doctors usually interpret this test along with: 

• CBC test
• CRP test
• Blood culture
• Clinical symptoms
• Imaging tests 

Procalcitonin is considered highly informative in emergency and intensive care settings. 

Procalcitonin Normal Range

To understand your test result, you need to know what is considered "normal."

Healthy Adults

• Normal: Below 0.1 ng/mL (nanogram per milliliter)
• Borderline: 0.1 - 0.25 ng/mL (low risk of bacterial infection)

Critically Ill/ Hospitalized Patients

PCT Level	Interpretation
< 0.1 ng/mL	Normal; Bacterial Infection Unlikely
0.1 - 0.25 ng/mL	Mild Elevation; Low Probability
0.25 - 0.5 ng/mL	Moderate; Possible Bacterial Infection
0.5 - 2.0 ng/mL	High Probable Bacterial Infection
> 2.0 ng/mL	Very High; Likely Bacterial Infection
> 10 ng/mL	Septic Shock: Serious Condition

Note: Reference ranges can vary slightly between laboratories. Always interpret results in consultation with your doctor. 

What Does a High Procalcitonin Level Mean?

The presence of high procalcitonin levels can be attributed to:

Bacterial Infections

• Sepsis
• Pneumonia
• Infection in the kidneys
• Infection in the blood
• Meningitis

Severe Inflammation

• Major injury
• Severe burns
• Surgery complications 

Infections related to organs

• Pancreatitis
• Abdominal infection

Certain Medical Conditions 

• Severe systemic infections
• Multiple organ dysfunction

What Does a Low or Normal Procalcitonin Level Mean?

Low or normal PCT is usually good news. This is what a low PCT means:

• Bacterial infection is not severe: Low PCT levels usually indicate that the body is not currently reacting to any bacterial infection.
• The infection might be viral: the body might be dealing with a viral disease such as influenza, the common cold, or most coronavirus cases, in which PCT levels remain low.
• No need for antibiotics: A low PCT level confidently avoids prescribing antibiotics for infections that won't respond to them anyway. 
• Reduction of antibiotic resistance: Consequently, a low PCT means doctors avoid using antibiotics unnecessarily, thus tackling the issue of antibiotic resistance
• Positive indicator of recovery: Low PCT levels indicate that the body is recovering from an infection. 

Symptoms That May Lead Your Doctor to Order This Test

The following symptoms may prompt your physician to request the test:

• High fever (above 101°F / 38.3°C) that does not respond to medication
• Shivering and chills
• Rapid heartbeat or breathing
• Mental confusion
• Low blood pressure
• Signs of organ dysfunction (respiratory problems and decreased production of urine)
• Prolonged hospitalization with suspected infection

All of these signs may indicate sepsis, and the test is used to confirm or rule out this diagnosis.

Can Procalcitonin Be High Without Infection?

Yes, in some cases.

Elevated levels may also occur due to:

• Major surgery
• Severe injuries
• Burns
• Certain cancers
• Prolonged shock
• Organ failure

This is why doctors do not rely on the test alone for diagnosis.

How Is the Test Performed?

A procalcitonin test involves taking a blood sample. To obtain this, a doctor will insert a needle into a vein and collect a small quantity of blood. The process takes only a few minutes.

Generally, there is no need for special preparation before the test. Patients don't need to fast before the procedure. The test results are available in 24 hours.

Book Your Procalcitonin Test at Redcliffe Labs

Order your procalcitonin test easily and conveniently from the comfort of your home with doorstep sample collection from Redcliffe Labs.

And along with each test, enjoy 4X Value Benefits:

• Smart Reports with Health Trends & Actionable Insights: Easy-to-understand health reports with scores that help track your trends over time. 
• Expert-Led Report Consultation: Guidance by experts in understanding test results and risks, giving you clear advice on the way forward. 
• AI Health Assistant for Everyday Health Guidance: Help with all questions related to your health, interpreting symptoms, and guidance for the first step. 
• Goal-Based Personalized Improvement Plans: Dietary and lifestyle advice to improve your health outcomes and prevent future illnesses. 

How Often Should Procalcitonin Be Monitored?

In Hospitalized Patients:

• Repeat the PCT test after 24 to 48 hours.
• A falling PCT indicates a positive response to antibiotic therapy.
• Increasing PCT may indicate the need for adjusting therapy.
• Helps doctors track recovery progress without guesswork. 

Outpatients/Home Patients:

• Usually, a one-time test is ordered for specific symptoms. 
• Not a routine or regular screening test. 
• The doctor will decide whether further testing is needed based on your condition.

How Doctors Use Procalcitonin to Guide Antibiotics

An important use of this test is to minimize unnecessary antibiotic use.

• If procalcitonin levels are low, physicians can prevent unnecessary antibiotic use.
• On the other hand, if procalcitonin levels are high, physicians can begin administering antibiotics immediately.

Moreover, physicians can repeat the tests to check whether treatment is working. 

Risks of the Procalcitonin Test 

The blood test is generally safe: 

Minor risks include: 

• Mild pain at the injection site
• Bruising
• Dizziness
• Rare infection at the puncture site

Can You Prevent High Procalcitonin Levels? 

As for the procalcitonin being a response marker rather than an illness itself, there is no direct way to "prevent" elevated PCT levels. However, you can take steps to reduce the risk of developing serious bacterial infections.

Preventive steps include: 

• Completing antibiotic courses fully
• Staying up-to-date with your immunization, including influenza and pneumococcus vaccines
• Practicing good hand hygiene to prevent the spread 
• Taking control of chronic medical conditions such as diabetes
• Seeking medical attention early when symptoms worsen instead of waiting

As the World Health Organization suggests, early diagnosis and appropriate treatment of infections are among the most effective ways to prevent sepsis.

When Should You See a Doctor?

Consult a doctor if you have:

• Persistent fever
• Sudden weakness
• Difficulty breathing
• Confusion
• Signs of infection after surgery
• Symptoms of sepsis

Early diagnosis can prevent complications.

Conclusion 

A procalcitonin test is quite helpful for diagnosing severe bacterial infections and detecting sepsis early. Although elevated readings suggest infection, procalcitonin test results must be reviewed alongside symptoms and other test findings by a qualified physician.

Early detection will certainly make it easier for doctors to prescribe appropriate medication. If your doctor recommends a procalcitonin test, trusted diagnostic providers like Redcliffe Labs can help with accurate testing and convenient sample collection services. 

FAQs

1. What is a normal procalcitonin level?

The normal value for procalcitonin is less than 0.05 ng/mL; however, some laboratories may use different ranges depending on their standards. Low levels often indicate that no severe bacterial infection is present. Yet, clinicians would not rely solely on the test result to determine the diagnosis, as other factors may be recommended.

2. Does high procalcitonin always mean sepsis?

High procalcitonin levels do not necessarily mean sepsis. Although an elevated value often indicates a bacterial infection and sepsis, you can also have a high procalcitonin level after a significant surgical operation, traumatic injury, extensive burn injuries, or pancreatitis.

3. Is fasting required for a procalcitonin test?

Normally, fasting is not required before a procalcitonin test, as it is a simple blood test that can be performed at any time of day. However, if other blood tests are required in addition to a procalcitonin test, your doctor may give you special instructions to prepare for the test.

4. Can viral infections increase procalcitonin?

Viral infections rarely elevate procalcitonin levels, making this test very useful for doctors in determining whether a patient has a viral or bacterial infection. However, under rare circumstances, procalcitonin levels may slightly rise due to severe viral infections.

5. Can children have this test done?

Yes, kids can be tested for procalcitonin when medical practitioners suspect a severe bacterial infection, such as sepsis, meningitis, pneumonia, or bacteremia. It can assist in determining the severity of the infection and help determine the best course of action. The test involves collecting a blood sample from the child.