Infectious Diseases Reflective Journal: Procalcitonin Review

This reflective journal critically analyzes a narrative review article on procalcitonin (PCT)-guided diagnosis and antibiotic stewardship in infectious diseases. The article explores PCT's potential beyond respiratory infections and sepsis, examining its utility in UTIs, meningitis, and other infections. The journal summarizes the article, highlighting its strengths, such as the comprehensive overview of PCT's limitations and its potential for reducing antibiotic use. Weaknesses include the lack of a systematic search strategy and potential for selection bias. The journal emphasizes the importance of PCT kinetics for antibiotic stewardship, leading to shorter treatment durations. It concludes by advocating for future studies using a more rigorous, systematic approach to overcome the limitations of narrative reviews and improve the clarity of the research questions. Overall, the journal underscores the need for strategies to combat antibiotic resistance and improve patient outcomes through informed diagnostic practices.

Running Head: INFECTIOUS DISEASES
Infectious Diseases
Name of the Student
Name of the University
Author Note

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Introduction
The reflective journal report is based on the article, “Procalcitonin-guided diagnosis and
antibiotic stewardship revisited” (1). The article is the narrative review on the potential of the
infection biomarker procalcitonin in infections other than the respiratory tract infections and
sepsis. The aim of the article is to determine the clinical utility for procalcitonin or PCT in other
infections such as Urinary tract infections, meningitis, and other superficial infections. The use
of antibiotic treatment can be challenging for physicians due to ambiguity in using the
conventional diagnostic markers such as C reactive protein and blood cultures in-patient
suspected to have infection. The limitation pertains to the sensitivity and specificity (2).
Antibiotic treatment for prolonged period has adverse consequences. In fifty per cent of the
cases, the antimicrobial use has been found inappropriate and is unneeded in inpatient setting (3).
It may lead to the antibiotic resistance and collateral damage such as “Clostridium diffiicile-
associated diarrhea”. Recently, there is an increasing focus on the Procalcitonin, as an infection
marker. Under normal circumstances it is produced by the thyroid C cells. However, in the case
of bacterial infections, PCT is produced by many body tissues and it parallels to the severity of
the inflammatory insult. Further, it is the prognostic indicator that the higher serum level of PCT
is associated with the risk of mortality (2, 4).
There is a growing body of literature on the use of PCT for the rationale use of the
antibiotics. Thus, strong scientific evidence is needed to diagnose the bacteria infection using
this marker, so that the antibiotic treatment can be reduced in duration when compared to other
standard care. Thus, it is important to determine the efficacy of the PCT guided therapy. The
benefits may include quick diagnosis, reduced hospital stay of patients even in severe sepsis and

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mortality (1, 3). If the clinical evidence is strong, the clinicians will be benefited. They can
quickly diagnose the bacterial infections and treat on time, to prevent the clinical outcomes. The
aim of the reflective journal is to summarise the selected journal article and critically evaluate
the content of the research paper. Lastly, the overall summary is discussed based on the critically
appraisal.
Summary of article
In the article by (1), the author has intended to update the clinicians on the new
indications for PCT after the review published in 2011 indicating the use of prolactin in
diagnosis and treatment of the lower respiratory tract infections and sepsis. This author of the
article has performed a narrative review of the studies published in the period 2012-2013. The
review includes various observational and interventional research and study designs. Most of the
study designs selected were randomised control trials (RCT), RCT with real life (registry), meta-
analysis of the RCTs, observational RCT of secondary analysis, only observational metaanalysis
study, and only observational study. These chosen studies have investigated the use of the PCT
in different types of infections and at different sites. The rationale for this narrative review is the
inappropriate use of the antibiotics. With the emerging bacterial infections and antimicrobial
resistance, there is an urgent call for intense efforts to deal with the self-limiting nonbacterial and
resolving diseases (5). There is a need of the “one size fits all” approach. This narrative review
by (1) may add to the growing body of literature, highlighting a useful strategy for antibiotics
treatment reduction.
In the given article, pulmonary site, the infections covered are AECOPD, Asthma,
bronchitis, community acquired immunity, and pulmonary fibrosis and upper respiratory

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infections. The infections related to heart studied are congestive heart failure, and endocarditis.
The infections related to abdominal region covered are pancreatitis, appendicitis abdominal
infections with peritonitis, and urinary tract infections. The blood related infections that are
considered for determining the efficacy of PCT are Blood stream infection, Neutropenia and
Severe sepsis/ shock. Some studies are included in the narrative review and deal with other
infections such as arthritis, erysipelas, meningitis, and postoperative infections. Lastly, the article
draws conclusion based on the results from different studies (1).
Critical evaluation of the article
The strength of the narrative paper is the flexibility of narratives (7). The author has
focused on the broad picture of the Procalcitonin-guided diagnosis. The article has presented a
comprehensive background on the chosen research area and the related gaps in this domain (1).
The article contains wide range of relevant information on the Procalcitonin-guided diagnosis
and its potential as infection biomarker. The strength of the study is the comprehensive details on
the limitations of PCT (6). The interpretation of role of PCT is made carefully. The drawback of
PCT related to suboptimal sensitivity and specificity was necessary to get idea of its clinical
implication (1, 2).
The literature review could have been presented in the article (1) precisely, instead of
directly starting with the review (8). The article grabs the reader’s attention as it had clear
question and focused on range of infections. The review has specified the type of the studies
considered that makes easy for the readers to comprehend the methodology. It is the advantage
of the study (9). However, the narrative review is limited due to lack of presentation of the
search strategy, inclusion and exclusion criteria. Thus, it remains ambiguous if the researcher had

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personal contact with the experts (8, 10). It is not clear if all the relevant studies in the chosen
time frame were considered or not. The quality of the studies chosen for narrative review does
not seem to be assessed and there is no hint on the assessment of the methodological quality.
This is the drawback of the study. Hence, the validity of the narrative review is doubtful although
the findings address the clinical question to some extent (11).
It is evident from the paper (1) that the PCT is promising in reducing the antibiotic
exposure. Thus, it will be highly beneficial for the patients suffering from the critically ill sepsis,
UTIs, acute heart failure, meningitis, postoperative infections and other infections. If the
antibiotics treatment can be reduced with PCT, it is added an advantage (12). Highlighting this
aspect is the strength of the article. The most interesting finding was the antibiotic stewardship
(for respiratory infection and sepsis) by monitoring PCT kinetics. It resulted in the shorter
antibiotic treatment duration in case of other infections (2). The emphasis on the PCT kinetics for
antibiotic stewardship for severe infections appeared to be the effective strategy to decrease the
mortality due to short duration of the antibiotic treatment by early cessation of therapy.
Highlighting these findings has positive clinical implications (1). This proves to be of prognostic
value related to disease severity (12).
The results are overall combined in a systemic manner, including all the studies selected.
Different infections and the role of PCT in diagnosis and treatment are well presented under
individual subheadings (13). The heterogeneity of the results are however, not considered by the
author (14). The reviewer does not mention the other parameters related to the PCT evaluation
such as odd ratio, relative risk, or p-value. It is not clear, if it was not mentioned or if it is not
applicable to this review. Thus, the presentation of the results is descriptive. The tabular
representation of the PCT cut off is mentioned among other parameters (15). The strength of the

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results section comes from the various settings that are useful for PCT-guided therapy. The
theme of recoding the PCT values on admission can be of great help to the clinicians as it was
found to reduce the antibiotic treatment in low risk situation (2, 3). The author at the end of the
review emphasise on the need of the comparison between CRP and PCT in terms of the
antibiotic stewardship. The review concludes with need of intense efforts to reduce the
inappropriate use of the antibiotics as also mentioned in other articles in this research area (1).
These additional factors can be useful and be applied as it might contribute to the change in the
clinical practice.
There are several limitations to the narrative review inspite of the background of the
broad topic. The nature of this type of research paradigm becomes too subjective in regards to
the type of studies to be included or excluded and the overall conclusion drawn (16). The
selection bias may lead to misleading results. The author has not conducted the systemic review
for each type of the infection in the concerned article. Only selected studies based on the
PubMed search were found and some were based on the author’s expertise, that makes the results
of the paper very enthusiastic due to subjective weighing of the studies chosen (1). Further, there
is a probability of bias, as most of the studies did not bind the patient. When large set of studies
are involved, it is challenging to determine and integrate the complex interactions (17).
The author of the article has presented a very less data on the CRP markers of infection.
Even for the other types of infections, PCT has not been well studied. This is the weakness of the
study. However, there is a significant evaluation of the PCT marker and its role in different types
of infection. The results related to this have been promising inspite of the limitations. The author
of the chosen article has restricted the research to a very short time period that is 2012-2016.
This is the drawback as the article has chance of missing relevant data pertaining to the research

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topic that has been published before this time (13). It may limit the reliability of the study and
the conclusions dawn (15). Overall, the results are based on the personal evaluation, beliefs,
thoughts and interpretations of the author. Since, it is an expert opinion; it can be considered an
evidence of lowest type. These studies are not as rigorous as they should be (16).
Systematic approach may eliminate the limitation of the narrative review. Thus, the
futures studies may take this rigorous approach. This approach is suggested as systematic review
is the reproducible and explicit summary of the health care interventions and their effects.
Further, systematic review involves two reviewers and follows a well-structured peer review
protocol. Since the reviewers review the methodology, the bias is reduced. The systematic
review indentifies the quality of the chosen study therefore; they are more transparent than the
narrative review. Further, systematic review is considered the cornerstone of the evidence based
practice as it focuses on clinical question and indentifies the best evidence (18). The narrative
question has established by developing a broad question. It should start with more clear and
focused question. The focused question can include the “population, intervention, comparison
and outcomes.” It is also called as PICO question in short and is effective in finding answers
more efficiently. This process decreases the element of vague and chance of getting unnecessary
results (19).
Summary and discussion
Based on the critical appraisal of the narrative review on the Procalcitonin-guided
diagnosis, and antibiotics stewardship it is evident that there is a need of finding solution that
will work as “all purpose” strategy. There is an emerging bacterial resistance to the antibiotics.
However, the prolonged use of bacteria has many adverse consequences such as collateral

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damage and diarrhea associated with C.difficle. Earlier, many studies have tried to determine the
efficacy of the PCT in the diagnosis and treatment of the bacterial infection. However, the focus
of these previous studies was mainly on respiratory tract infections and sepsis. The narrative
review however highlights the clinical utility for PCT in other infections such as Urinary tract
infections, meningitis, and other superficial infections. This deviation in focus was necessary for
the clinicians struggling with the prolonged use of the antibiotic therapy.
Based on the findings of the narrative review, there are many clinical situations where the
PCT may be useful. It includes the differentiation of the bacterial and the viral respiratory tract
infection. PCT will be useful in the diagnosis of the septic arthritis, renal involvement in the
paediatric urinary tract infections and distinguish between the bacterial and the viral meningitis.
Other clinical situation were PCT can be used include monitoring of the response to the
antibacterial therapy and diagnosis of the postoperative infection (systemic secondary infection)
or cases of trauma, burns ad transplants (2, 3, 5). According to (4), clinicians should not make
the decisions regarding the antimicrobial therapy based on the serum level of PCT. Rather; it will
be effective if PCT is placed in the clinical context of each patient scenario (1, 4). The clinicians
must consider the site of possible infection, the extent of bacteria invasion and the degree of
illness. Other clinical data must also be considered, pertaining to the situation. However, once
the use of PCT is approved, the factors to be considered are cost. It is expensive than CRP but
hold greater value for determining the cessation of antibiotics. If there is a decreased antibiotic
use, the cost savings through the use of the PCT can be identified.
Based on the emerging studies, it can be concluded that, PCT appears to be persuasive
and is an evidence based approach to use antibiotics more rationally. This article is like an eye-
opener for diagnosis of different infections using PCT. There is a need of further research to

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compare the effectiveness of the CRP and PCT for diagnosis of adult emergency department
patients.

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