Procalcitonin

[lymphocyte]

I'm trying to gather my thoughts around procalcitonin as a biomarker for both bacterial infection and sepsis. I'm just curious what the state of play is at your institution or your own practice pattern?

The data seem compelling. There was the Lancet patient-level meta-analysis as well as a Cochrane review that demonstrated a mortality benefit in procalcitonin-guided antibiotic de-escalation compared to clinical judgement alone in the setting of respiratory infections in ICU.

Beyond antibiotic de-escalation, I've had a few cases where it has been immensely helpful in ruling OUT septic vasoplegia and establishing a better haemodynamic paradigm in the first few hours of resuscitation (where I work, the qualitative screen comes back in 30 minutes). One case in particular was somebody falling down the RV death-spiral from severe pHTN in the setting of pneumonia. I had a lot of trouble with the bedside TTE given the body habitus. But he had frank stigmata of RHF on exam, a low PCT, and BNP around 15,000. I turned him around pretty quickly in ED with low-dose doboutamine, diuretics, cranking up the oxygen, and stopping all IVF. It was very satisfying in the end but maybe introduced a lot of bias in my approach.

I also get the issues around industry funding around some of the trials. However, overall, there seems to be a signal of benefit but it's still relatively new where I work, especially using it in adults.

Schuetz P, Wirz Y, Sager R, et al. Effect of procalcitonin-guided antibiotic treatment on mortality in acute respiratory infections: a patient level meta-analysis. Lancet Infect Dis. 2018;18(1):95-107. Effect of procalcitonin-guided antibiotic treatment on mortality in acute respiratory infections: a patient level meta-analysis. - PubMed - NCBI

Schuetz P, Wirz Y, Sager R, et al. Procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections. Cochrane Database Syst Rev. 2017;10:CD007498. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD007498.pub3/full

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[sluggs]

You raise a number of interesting issues here.

I have never gone as far as using PCT results to guide the hemodynamics of resuscitation-- you can be in cardiogenic shock and still have a SIRS response, or be dry for other reasons (ie you are cold and dry and need fluids). You can also (rarely) be septic and be volume overloaded-- the ER gave you more fluid than you needed, or you have not deteriorated into distributive shock yet. I would not use PCT to "elucidate" these hemodynamics.
However, there is a great place for PCT, despite controversy surrounding the data. If there is some low likelihood that a patient has an infection (think DKA that ran out of insulin, has a wbc of 12, a low grade fever; a 75 year old nursing home guy with a weakly positive UA a normal WBC, low grade fever, negative CXR). These patients may or may not get a quick dose of abx in the ED, but if PCT is negative, and signs of infection don't progress, the negative PCT would be further justification to stop abx. It is part of the diagnostic puzzle.
If you had a patient with fever, high WBC, and a large consolidation, a (surpirsingly alothough it could happen) negative PCT would not be a justification to stop abx.
A very wise pulmonologist once told me "Most diagnostic tests are worthless unless you have a pre-test probablility or pre-test differential."

 

[deleted697535]

Its old news in Europe. Maybe 10 years ago it was hugely promising. I remember reviewing an article on it in 2016 for our journal club and thinking it was amazing but the old timers ripped it up. Industry pushed it beyond belief

 

[AdmiralChz]

Its old news in Europe. Maybe 10 years ago it was hugely promising. I remember reviewing an article on it in 2016 for our journal club and thinking it was amazing but the old timers ripped it up. Industry pushed it beyond belief

Yes. Treat the patient, not a number! Old adage that stays true.

 

[SurfingDoctor]

Biomarkers in their current state are crap. Endotypes... maybe...someday.

 

[WheezyBaby]

The procal literature I've read is a mess of contradictory studies. The strongest data is antibiotic deescalation and duration of therapy in the setting of pneumonia and sepsis. I think it's reasonable to use it here. I will also occasionally use it to justify my decision to withhold antibiotics in a patient who I don't think needs it (low pretest probability) but in general the data for utility of procal in withholding antibiotic initiation is poor and I would never use it in this way in any remotely ill patient. I would be cautious as well extrapolating pneumonia literature to COPD, particularly for ICU COPD. I'm still forming my opinion here, but I think there may be some utility as well in risk stratification of neutropenic fever (never to withhold antibiotics, just to assist in gestalt determining who may have something malignant driving their fever).

In discussions with my ID colleagues, their opinions seem to be all over the place. One of the ones I hold in highest regard is all aboard the procal train, but I can't get myself there.

 

[aafisahar]

procal was never designed as a rule-in/rule-out test. I've seen negative procals (eg <0.20) and patients bacteremic with pneumococcus. We had an M&M on a patient who had a COPD exacerbation, negative procal, who ultimately got a bronch for worsening infiltrates and they had textbook pneumonia. Patient eventually grew out HiB in her sputum.

I personally hate procal, never order it myself.

 

[jdh71]

I'm trying to gather my thoughts around procalcitonin as a biomarker for both bacterial infection and sepsis. I'm just curious what the state of play is at your institution or your own practice pattern?

The data seem compelling. There was the Lancet patient-level meta-analysis as well as a Cochrane review that demonstrated a mortality benefit in procalcitonin-guided antibiotic de-escalation compared to clinical judgement alone in the setting of respiratory infections in ICU.

Beyond antibiotic de-escalation, I've had a few cases where it has been immensely helpful in ruling OUT septic vasoplegia and establishing a better haemodynamic paradigm in the first few hours of resuscitation (where I work, the qualitative screen comes back in 30 minutes). One case in particular was somebody falling down the RV death-spiral from severe pHTN in the setting of pneumonia. I had a lot of trouble with the bedside TTE given the body habitus. But he had frank stigmata of RHF on exam, a low PCT, and BNP around 15,000. I turned him around pretty quickly in ED with low-dose doboutamine, diuretics, cranking up the oxygen, and stopping all IVF. It was very satisfying in the end but maybe introduced a lot of bias in my approach.

I also get the issues around industry funding around some of the trials. However, overall, there seems to be a signal of benefit but it's still relatively new where I work, especially using it in adults.

Schuetz P, Wirz Y, Sager R, et al. Effect of procalcitonin-guided antibiotic treatment on mortality in acute respiratory infections: a patient level meta-analysis. Lancet Infect Dis. 2018;18(1):95-107. Effect of procalcitonin-guided antibiotic treatment on mortality in acute respiratory infections: a patient level meta-analysis. - PubMed - NCBI

Schuetz P, Wirz Y, Sager R, et al. Procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections. Cochrane Database Syst Rev. 2017;10:CD007498. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD007498.pub3/full

It's just an extra data point. Use in context. Can be confounding.