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Test Code PROCLT Procalcitonin LAB2677

Performing Laboratory

UnityPoint The Finley Hospital

Test Method

Chemiluminescent immunoassay (sandwich principle); Roche cobas Pro

Performance

Testing is performed Monday through Sunday.
Routine: Typically completed within 4 hours after the specimen arrives at the laboratory.
STAT: Typically completed within 1 hour after the specimen arrives at the laboratory.

Specimen Requirement

  1. Lithium heparin plasma (Green) is the specimen of choice. 500μL.
  2. Serum (Red/Gold) and EDTA (Purple) plasma are also acceptable sample types.
  3. Gel tubes are acceptable.
  4.  It is recommended that the serum or plasma be separated from contact with cells within 2 hours from time of collection.
  5. Procalcitonin specimens are stable for 24 hours at 20-25°C, 48 hours at 2-8°C, and 12 months at -20°C.

Useful For

Sepsis is a daily challenge in the hospital setting. Today, various therapeutic strategies are known to improve survival in patients with sepsis. Early assessment is important for determination of the appropriate treatment.
 

PCT is the prohormone of the hormone calcitonin, but PCT and calcitonin are distinct proteins. Calcitonin is exclusively produced by C‑cells of the thyroid gland in response to hormonal stimuli, whereas PCT can be produced by several cell types and many organs in response to proinflammatory stimuli, in particular by bacterial products.  In healthy people, plasma PCT concentrations are found to be below 0.1 ng/mL. Depending on the clinical background, a PCT concentration above 0.1 ng/mL can indicate clinically relevant bacterial infection, requiring antibiotic treatment. PCT levels rise rapidly (within 6‑12 hours) after a bacterial infectious insult with systemic consequences. The magnitude of the increase in PCT concentration correlates with the severity of the bacterial infection. At a PCT concentration > 0.5 ng/mL, a patient should be considered at risk of developing severe sepsis or septic shock. On the other hand, the relief of the septic infection is accompanied by a decrease in the PCT concentration which returns to normal with a half-life of 24 hours, i.e., the continuous decline of PCT is indicative of effective source control measures and has been implicated in the safe de-escalation of antibiotic therapy.
 

By evaluating PCT concentrations, the physician may use the findings to aid in the risk assessment of critically ill patients for progression to severe sepsis and septic shock. In addition, the change of PCT levels over time offers information about the risk of mortality after diagnosis of severe sepsis or septic shock.
 

Early after multiple traumas, major surgery, severe burns, or in neonates, PCT levels can be elevated independently of an infectious process, but the return to baseline is usually rapid. Viral infections, bacterial colonization, localized infections, allergic disorders, autoimmune diseases, and transplant rejection do not usually induce a significant PCT response (values < 0.5 ng/mL). Therefore, PCT is an important marker enabling specific differentiation between a bacterial infection and other causes of inflammatory reactions.

Reference Values

Results > 0.15 ng/mL will flag as abnormal

Adults & Children ≥ 72 hours of
age: ≤ 0.15 ng/mL

Children < 72 hours of age: <
2.0 ng/mL at birth, rises to ≤ 20 ng/mL at 18-30 hours of
age, then falls to ≤ 0.15 ng/mL by 72 hours of age

  • < 0.5 ng/mL: low risk of sepsis
  • 0.5-2.0 ng/mL: possible risk of sepsis, retest within 6-24
    hours recommended
  • > 2.0 ng/mL: high risk of sepsis and/or septic shock

Sepsis Initial Antibiotic Use Algorithm using
Procalcitonin (PCT) value
Strongly consider antibiotic initiation in all patients with
suspicion of infection.

  • <0.25 ng/mL Antibiotic use strongly discouraged*
  • 0.25-0.49 ng/mL.  Antibiotic use discouraged.
  • >0.5-1.0 ng/mL.  Antibiotic use encouraged.
  • >1.0 ng/mL.  Antibiotic use strongly encouraged.

* Consider alternative diagnosis. Repeat PCT in 6-12 hours if
antibiotics not begun. If clinically unstable, immunosuppressed or
high risk consider overruling.
If patient is treated, consider repeating daily for 3 days  to
consider early antibiotic cessation (see next algorithm).


Sepsis Diagnosis FOLLOW-UP Antibiotic Use Algorithm using
Procalcitonin values

  • <0.25 ng/mL.  Cessation strongly encouraged.
  • 0.25-0.49 ng/mL or drop of 80 %. Cessation encouraged.
  • 0.5 ng/mL and decreased by <80%. Cessation discouraged.
  • 0.5 ng/mL, rising, or not decreasing. Cessation strongly
    discouraged.

A PCT value which is rising or not declining at least 10% per
day is a poor prognostic indicator and suggestions infection is not
controlled.  Consider expanding antibiotic coverage or further
diagnostic evaluation.
 

Lower respiratory tract infection (LRTI) Antibiotic Use
Algorithm using Procalcitonin value.

  • <0.1 ng/mL.  Antibiotic use strongly discouraged.*
  • 0.1-0.24 ng/mL.  Antibiotic use discouraged.
  • >0.25-0.5 ng/mL.  Antibiotic use encouraged.
  • >0.5 ng/mL.  Antibiotic use strongly encouraged.

* Consider alternative diagnosis.  Repeat PCT in 6-12 hours
if antibiotics have not begun and there is no clinical
improvement.  IF clinically unstable, immunosuppressed, or
high risk consider overruling.
If patient is treated, repeat every 2-3 days to consider early
antibiotic cessation (see next algorithm).
 

Lower Respiratory tract infection diagnosis FOLLOW-UP
Antibiotic Use Algorithm using Procalcitonin values.

  • <0.1 ng/mL or drop of >90% .  Cessation strongly
    encouraged unless clinically unstable.
  • 0.1-0.24 ng/mL. or drop of 80 % – Cessation encouraged unless
    clinically unstable.
  • >0.25-0.5 ng/mL.  Cessation discouraged.
  • >0.5 ng/mL.  Cessation strongly discouraged.

If PCT rising or not adequately decreasing, consider possible
treatment failure and evaluate for need for expanding antibiotic
coverage or further diagnostic evaluation.

CPT Code Information

84145  Procalcitonin

LOINC Code Information

75241-0  Procalcitonin (Mass/Volume) in Serum or Plasma by
Immunoassay