Procalcitonin
Objectives
• Review current data on procalcitonin
• Review its use at UCI MC
What is Procalcitonin?
• Precursor of hormone calcitonin
• Normally undetectable in healthy individuals
• Synthesized by thyroid C cells
– Also released by liver, kidney, muscle, fat cells in response to
bacterial toxins
• After exposure to toxins, serum levels of PCT increase within 2-4
hours, peaking ~14 hours (Kojic et al)
– PCT may also be elevated in non-infectious conditions (trauma,
surgical procedures, pancreatitis, renal impairment) (Kojic et al)
The Data on Procalcitonin
•
Prospective, observational cohort study by Anand et al sought to determine role of procalcitonin
(PCT) in differentiating culture-negative sepsis from non-infectious SIRS
–
Found that culture-negative sepsis patients had a significantly higher PCT relative to non-infectious SIRS
patients
•
Some studies suggest that PCT is not a helpful biomarker (Tang et al)
–
•
Sensitivity and specificity of 71%
Heyland and colleagues reviewed 5 RCTs to evaluate the effect of PCT-guided antibiotic strategies
on clinical and economic outcomes
–
Found that there was no effect of PCT-guided strategy on hospital mortality, ICU or overal hospital length
of stay, however it may have reduced overall costs of care due to shortened duration of antibiotic
administration
•
Similarly, Christ-Crain and colleagues looked at PCT-guided therapy for management of lower
respiratory tract infections
–
Found that PCT led to decreased use of antibiotics and no change in clinical outcome
Use of PCT at UCI MC
•
Cost of PCT assay (self-pay): $35.45
•
PCT interpretation at UCI
– <0.5 systemic infection not likely
– 0.5-2.0 systemic infection possible, moderate risk of progressing to severe systemic infection
– 2.0-10 systemic infection likely (unless other cause of inflammation is known), high risk of
progressing to severe systemic infection
– >10 major SIRS, almost always due to severe bacterial sepsis
•
Chart-reviewed 15 ward patients
– Reviewed PCT levels
– Reviewed culture, imaging data
– Reviewed antibiotic administration
– Documentation of PCT use / impact on management
The Raw Data
Pt
SIRS/Sepsis?
PCT
Rad
Cx
Abx
Documentation / Dx
1
No
<0.05
Yes
No
Yes
Ordered – pneumonia
2
Sepsis
<0.05
Yes
Yes
(G+)
Yes
No – endocarditis, joint
3
2 SIRS
0.07
No
Yes (G-) Yes
No – urine colonization?
4
1 SIRS
0.09
No
Yes (G-) No
No – asymp. bacteriuria
5
1 SIRS
0.17
No
No
No
No – tumor pain
6
2 SIRS
0.2
No
No
Yes
Ordered – UTI (UA neg)
7
2 SIRS
0.23
No
No
No
No – sickle cell pain crisis
8
Sepsis
0.37
Yes
Yes (G-) Yes
No – abscess
9
SIRS
0.87
No
No
No – aortic dissection
10
SIRS  sepsis
0.91
No
Yes (G-) Yes
No – cholangitis
11
2 SIRS
1.13
?
No
Yes
No – CAP?
12
2 SIRS
1.42
No
No
No
No
13
Sepsis
1.45
No
Yes
(G+)
Yes
Ordered – CAP
14
Sepsis
4.33
Yes
No
Yes
No – CAP
No
Some Observations
PCT Interp
N
e/o Infection
Abx
Not Likely
8
5 (63%)
5 (63%)
Possible
5
2 (40%)
3 (60%)
Likely
2
2 (100%)
2 (100%)
•
Difficult to assess utility of PCT as there are no clear guidelines
•
In our patients, 87% had PCT levels with low likelihood of infection, or possible infection
–
•
At UCI, no difference in antibiotic use in the “infection not likely” versus “infection possible” groups
Never documented whether PCT had a role in clinical decision-making
–
Antibiotics were not discontinued based on a low PCT
–
Even if suspicion for infection was low, antibiotics were still given in some instances
–
Antibiotics were empirically given if a pt was thought to be septic
Conclusions
• This $35 test is sometimes used to determine the
likelihood of infection at UCI MC
• However, it is not clear whether PCT levels have any
impact on the decision to administer antibiotics
– Documentation should be updated regarding PCT levels and
their impact on management decisions
– For those with elevated PCTs, trending PCT could be
considered to determine duration of antibiotic administration
References
•
Anand D, Das S, et al. Procalcitonin as a rapid diagnostic biomarker to differentiate between
culture-negative bacterial sepsis and systemic inflammatory response syndrome: A prospective,
observational, cohort study. J Crit Care 2015 Feb;30(1):218.e7-12.
•
Christ-Crain M, et al. Effect of procalcitonin-guided treatment on antibiotic use and outcome in
lower respiratory tract infections: cluster-randomised single-blinded intervention trial. Lancet
2004;363:600-07.
•
Heyland DK, Johnson AP, et al. Procalcitonin for reduced antibiotic exposure in the critical care
setting: A systematic review and an economic evaluation. Crit Care Med 2011;39(7):1792-99.
•
Kojic D, Siegler BH et al. Are there new approaches for diagnosis, therapy guidance and outcome
prediction of sepsis? World J Exp Med 2015 May 20;5(2):50-63.
•
Tang BMP, Eslick GD, et al. Accuracy of procalcitonin for sepsis diagnosis in critically ill patients:
systematic review and meta-analysis. Lancet Infect Dis 2007;7:210-17.