What is procalcitonin PCT (serum) lab test?
Procalcitonin is a prohormone of calcitonin, which is naturally produced by body cells in response to bacterial infections, tissue injury & sepsis. Therefore, it is used as a marker in sepsis (body's serious, overwhelming, and life-threatening inflammatory response to bacterial infection). In a normal individual, procalcitonin levels are normal and rarely elevate. This laboratory test helps in detecting procalcitonin levels and determines widespread distribution of bacterial infection in body.
Why is PCT serum lab test done?
This test is useful in detecting sepsis and severe bacterial infections in early stages. It is done:
- In diagnosis of renal involvement in UTI (urinary tract infection) in children
- In diagnosis of bacterial infection in neutropenia (abnormally low concentration of neutrophils) patients
- In diagnosis, risk stratification & monitoring of septic shock
- In diagnosis differentiating b/w viral & bacterial meningitis
- In diagnosis of systemic secondary infection post-surgery, & in severe trauma/burn/multiorgan failure
- Diagnosis differentiating b/w viral pneumonia & community acquired bacterial pneumonia
- In antibacterial therapy monitoring (checking therapeutic response)
- What is the purpose of PCT blood test?
It is used to help determine risk of critically ill person going towards severe sepsis and septic shock, or risk of dying. Also distinguish b/w non-bacterial and bacterial infections
- What is normal range for PCT in blood?
The reference range above 72 hours of age is 0.15 ng/mL or less. And the range is very low below detection.
- Which reasons cause elevated PCT?
Apart from bacterial infections, recent major surgery, severe burns, severe trauma, & prolonged cardiogenic shock lead to high levels of PCT in blood
- Which are 3 stages in sepsis?
Its three stages are sepsis, severe sepsis, and then septic shock
INTERPRETATION OF THE RESULTS:
- Age > 72 hours & PCT value 0.00-0.10 ng/mL: Interprets that there is unlikely a significant bacterial infection
- Age > 72 hours & PCT value 11-0.50 ng/mL: Interprets a significant bacterial infection is possible, retest 12-14 hours, and consider clinical picture/other diagnostic tests
- Age > 72 hours & PCT value 51-2.00 ng/mL: Interprets that significant bacterial infection is likely, consider clinical picture/other diagnostic tests
- Age > 72 hours & PCT value >2.00 ng/mL: Likely that significant bacterial infection is present, & patient is at risk for bacterial sepsis or septic shock.
While diagnosing bacteremia in neonates (0 to 72 hours of age):
- Procalcitonin values increase from birth and reach peak values at about 24 hours and gradually decrease after 48 hours of life
- Hence, during first 72 hours of life, different reference ranges will be applied on newborn infant at different age hours.
- PCT level is higher in newborns suffering from early sepsis than non-infected newborns.
- Adult ranges given above will apply after 72 hours or more after birth.
You get tested to diagnose sepsis, determine risk of progressing towards severe sepsis/septic shock, identify bacterial infection, & differentiate b/w bacterial and nonbacterial conditions. It is also done to guide during antibiotic treatment.
