Infectious Diseases: Procalcitonin-Guided Diagnosis Report

This reflective journal report critically evaluates a research article focused on the clinical utility of procalcitonin (PCT) as a biomarker for various infections, excluding sepsis and respiratory-related infections. The article, a narrative review of studies published between 2012 and 2013, explores the potential of PCT in diagnosing infections like meningitis and urinary tract infections, aiming to reduce the irrational use of antibiotics. The report summarizes the article's findings, highlighting the significance of PCT in guiding antibiotic stewardship and potentially reducing treatment duration, hospital stays, and mortality. It also provides a critical evaluation of the article, discussing its strengths, such as its comprehensive overview and clear research question, and its limitations, including the lack of a detailed search strategy and potential biases due to the subjective nature of the study design. The report concludes by emphasizing the promising implications of PCT in enhancing clinical practice and advocating for a more rigorous systematic approach in future studies.

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 reviews the article, “Procalcitonin-guided diagnosis and
antibiotic stewardship revisited” (1). It is the narrative review on the utility of the infection
biomarker procalcitonin. The article is focused on the potential of the biomarker in infections
excluding the sepsis and respiratory related infections. The aim of the chosen article was to
determine the importance of the procalcitonin or PCT clinically. The article tend to highlight
the clinical utility of this biomarker in infections such as meningitis, Urinary tract infections,
and others. There lies an ambiguity in using the convectional diagnostic markers. It makes
challenging for the physician to use the antibiotic treatment for patients with high C reactive
protein and whose blood cultures indicate of infections. These conventional diagnostic
markers have several limitations and the main ones poor sensitivity and specificity (2). When
the antibiotic treatment is used for prolonged period, it has adverse consequences. The
antimicrobial use was found unneeded in 50% of the cases (3) and was inappropriate in
inpatient setting. The consequences may include antibiotic resistance. Collateral damage such
as C. difficle associated Diarrhea may be other outcomes. There is greater focus on PCT
recently due to its increasing attention as infectious marker. It is produced by the thyroid C
cells under normal circumstances. In case of bacterial infections, many body tissues produces
PCT. This condition may be similar to the severity associated with the inflammatory insult. In
addition, PCT is the prognostic indicator. A risk of mortality is indicated with the higher
serum level of PCT (2,4).
There is increasing literature evidence on the importance of PCT and its application
for using antibiotics rationally. There is a need of strong scientific evidence to use this marker
for diagnosing the bacterial infection. It will help in reducing the antibiotic treatment for
prolonged period. In comparison to other treatment or standard of care the duration of the

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antibiotic treatment can be reduced. Hence, the efficacy of the PCT guided therapy is
important to be determined. The benefits of PCT may include faster diagnosis, and decrease
in mortality by reducing the hospital stay of patient even in severe sepsis (1,3). The clinicians
will be benefitted by having a strong clinical evidence. Treatment can be enhanced by faster
diagnosis of the bacterial infections. Patient can be treated on time to ensure positive health
outcomes. The reflective journal aims to critically evaluate the selected journal article and
briefly summarise the content of the research paper. Based on the critical appraisal, the
overall summary is discussed.
Summary of article
In the selected research article, the new indications for PCT has been highlighted by
the author to update the clinicians on the potential biomarker. The author presented the article
as an outcome of the review published in 2011 that highlighted the PCT use in diagnosis and
treatment of sepsis and lower respiratory tract infections. Thus, the author of the chosen
article conducted a narrative review of the PCT studies published between 2012-2013. In this
review, the author considered various observational and interventional research and study
designs. The study designs selected mostly includes RCT (randomised control trials), meta-
analysis of the RCTs, RCT with real life (registry), observational RCT of secondary analysis,
only observational studies and observational metaanalysis studies. These studies were
preferred by the author as they are highly focused on the use of the PCT for different
infection types at various sites. The focus of author for this narrative review was the irrational
use of the antibiotics. With plethora of bacterial infections emerging and increase in the
antimicrobial resistance, there is a call for intense efforts to fight the “self-limiting
nonbacterial and resolving diseases” (5). As per the scenario, “one size fits all” approach is

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needed in present condition. Therefore, this narrative review (1) may add to the existing
literature and help with strategy for reduction of the antibiotics treatment.
The article covers the pulmonary related infections such as Asthma, pulmonary
fibrosis, community acquired immunity, AECOPD, bronchitis, and upper respiratory
infections. The heart related infections studied by the author includes congestive heart failure,
and endocarditis. The narrative review presented the abdominal region infections such as
pancreatitis, appendicitis and associated peritonitis. It also covered the urinary tract
infections. The narrative review also considered the blood related infections for identifying
the efficacy of PCT. It includes Neutropenia, Blood stream infection, and Severe sepsis/
shock. The narrative review also includes other infections such as erysipelas, meningitis,
arthritis, and postoperative infections. Based on the analysis of the results from different
studies, the article draws conclusion pertaining to significance of PCT (1).
Critical evaluation of the article
The flexibility of the narratives is the strength of the article selected (6). The broad
picture of the PCT guided diagnosis was highlighted. The article by (1), comprehensively
discussed the background of the research area chosen for the review and the considered the
research gaps in this domain. The information on PCT was relevant and a bulk of related
information pertaining to PCT as potential infection marker was given. The author of the
narrative review presented the limitations of PCT. It constitutes the strength of the paper (6).
The author made a careful interpretations of the role of PCT. To get the idea on the clinical
implications, it was necessary to know the drawback of PCT related to suboptimal sensitivity
and specificity (1, 2).
The literature review on the topic was missing in the review. Precisely the author (1)
could have presented the previous literature. Instead, the article directly started with the

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review. However, the article was good enough to catch the reader’s attention. It was due to
the clear research question along with the focus on range of infections. It is easy for the
readers to understand the methodology as the author specified the types of the studies
considered for the narrative review (8). This adds to the strength of the study (9). The
narrative review however, lacks details on the search strategy. The author did not also
mention the inclusion and exclusion criteria. It remains ambiguous if the researcher
personally contacted the previous study experts (8, 10). In the chosen year slaught, the author
may not have considered all the relevant literature. Further, there is no indication by the
author on the assessment of the quality of the studies chosen for narrative review. There is no
hint in the paper regarding the assessment of the methodological quality. It can be considered
as a drawback of the narrative review. The validity of the paper appears to be doubtful even if
it is successful to some extent in addressing the clinical question (11).
In the paper (1), it is evident that the PCT is promising to reduce the duration of the
antibiotic treatment. It will be greatly useful to the clinicians if PCT can reduce the antibiotics
treatment. It will benefit the patients with UTIs, critically ill sepsis, acute heart failure,
postoperative infections, meningitis and other infections (12). The author highlighting this
aspect in the study is considered strength of the narrative review. The interesting finding
appeared to be the “antibiotic stewardship” by monitoring PCT kinetics and particular focus
on the respiratory infection and sepsis. In case of other infections, a shorter duration of the
antibiotic treatment was observed (2). This short duration of antibiotics is the effective
strategy to decrease the mortality. It will help in early cessation of therapy for severe
infections. Therefore, it was effective to emphasis on the PCT kinetics for antibiotic
stewardship. These findings seems to have positive clinical implications (1, 12). It indicates
the prognostic value in disease severity.

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The author has combined the results in the systematic manner that is inclusive of all
the studies chosen. The narrative review has well presented the different infections, their
diagnosis and treatment by PCT under different subheadings (13). The author however, did
not consider the heterogeneity of the results (14). There is missing information on other
parameters related to PCT evaluation. This comprises of the relative risk, odd ratio or p-
value. It cannot be comprehended if the author did not mention these parameters because it is
not applicable. If it was applicable not mentioning them is the drawback of the review. The
paper provided a descriptive review of the results while mentioning about the PCT cut off in
the tabular format (15). It appears from the results that PCT guided therapy is useful in
various setting. The clinicians can record the PCT values on the admission of the patient. It
will be of great help to the clinicians as in low risk situation the treatment using antibiotics
can be reduced (2, 3). Further, strength of the paper includes an emphasis on the antibiotic
stewardship while highlighting the need of comparison between CRP and PCT. There is a
serious effort from the author to bring into limelight the ability of the PCT to reduce the
inappropriate use of the antibiotics. This was greatly emphasised by the author relating with
the research of other researchers in the chosen subject (1). These additional factors are
applicable and are useful to contribute to the change in the clinical practice.
Several limitations were apparent in the narrative review. The nature of the study
design is too subjective. In this research paradigm, an overall conclusion is drawn based on
type of studies included and excluded (16). The results may be misled due to bias. In the
concerned narrative review, the author has not conducted the systemic review for each type
of the infection mentioned. Only some of the studies were extracted from the PubMed search.
Some of the studies included were based on the author’s expertise. Overall, it makes the
results of the paper interesting. Due to subjective weighing of the studies chosen, the findings
are enthusiastic (1). In some of the studies chosen by the author the patients are not blinded.

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There is a probability of bias. In case of large set of studies, it is challenging to deduce and
integrate the complex interactions (17).
There is a very less information pertaining to the CRP markers of infection. The
author should have presented some more data on this factor. PCT is not well studied even for
other types of infections. It is the drawback of the narrative review. However, the strengths
overpower the weaknesses of the study. There is a proper evaluation of the PCT marker with
respect to different infections. Despite the limitations, the results from the narrative review
appears to be promising. In the narrative review the author has set a year frame that is 2012-
2016 for choosing the studies on PCT. This is a very short time period as too many studies
may not have been published on PCT. It can be considered a drawback of the study. There is
a high chance that other relevant articles that are published beyond this period may have good
amount of data on PCT efficacy. The author might have missed this information and it may
be relevant to clinical question (13). Thus, the chosen timeframe constitutes the drawback of
the study. There is a chance that this drawback limits the reliability of the study. It may affect
the conclusions drawn from the findings (15). The results are based on the personal valuation
of the author. The conclusion is drawn based on the author’s beliefs, thoughts and
interpretations of the data from various studies. It is an expert opinion and this papers are
considered to be an evidence of moderate-low type (16). This type of study is not rigorous
and is considered as low strength of evidence.
The limitations of the narrative review can be eliminated by taking the systematic
approach. In future, the author can take this rigorous approach for studies on this area.
Systematic review approach is suggested for explicit and reproducible summary of the health
care interventions and their effects. In this approach, usually two reviewers are involved.
Systematic review involves well-structured peer review protocol. The bias can be reduced by
the involvement of two reviewers in scrutinising the methodology of the studies. The

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systematic reviews are known to be more transparent in comparison to the narrative reviews.
It is because the systematic reviews well identify the quality of the chosen study. For
implementing the evidence-based practice the systematic review can be considered as
cornerstone as it helps in identifying the best evidence focusing on the clinical question (18).
The author of the narrative review has chosen a broad question. Instead, it is recommended to
use clear and focused question. It is recommended to use PICO framework as it deals with
the specific clinical question that comprise of four parameters that are the “population,
intervention, comparison and outcomes.” The PICO questions are short and very specific
about the clinical query to be conducted. It is effective in finding clinical answers more
efficiently. It eliminates the factor of vagueness and reduces the prospects of obtaining
irrelevant results (19).
Summary and discussion
The critical review of the narrative on the Procalcitonin-guided diagnosis, and
antibiotics stewardship indicates a need of developing a “all purpose” strategy to reduce the
antibiotic treatment. When the antibiotic treatment is used for prolonged period, it has
adverse consequences. The consequences may include antibiotic resistance and collateral
damage such as C. difficle associated Diarrhea. The need of PCT mediated diagnosis for
different types of infection is urgent considering the growing bacterial resistance to the
antibiotics. Many researchers have tried to determine the efficacy of the PCT guided
diagnosis in treating the bacterial infections. However, the previous studies have mainly
focused on the respiratory tract infections and sepsis. The clinical utility of the PCT is well
documented in the paper particularly in regards to other infections such as meningitis,
Urinary tract infections, and other superficial infections. This focus on other infections unlike

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the monotonous respiratory infections was needed. It is useful for clinicians who are
struggling with the use of the antibiotic therapy for prolonged period.
There are many clinical situations highlighted by the narrative review were PCT can
be effective. It may be useful for the differentiation of the bacterial and viral infection related
to respiratory tract. PCT may be useful for differential diagnosis of bacterial and the viral
meningitis, renal involvement in the paediatric urinary tract infections, and the diagnosis of
the septic arthritis. PCT can be also be used for other clinical situations such as monitoring
the response to the antibacterial therapy. Postoperative infections can also be effectively
diagnosed with PCT. It can be also useful for identifying the systemic secondary infections
and infections related to the transplants, burns, cases of trauma and other injuries (2, 3, 5).
The clinicians should not consider the serum level of the PCT to make decisions regarding
the antimicrobial therapy. Instead, one must consider the individual patient scenario placing
PCT (1, 4). The clinicians must consider the degree of illness, the extent of bacteria invasion,
and site of possible infection before making clinical decision. Cost is the limiting factor for
PCT, which must be considered one its use is approved. It is expensive than CRP. However,
it holds greater value in determining the infection. It has potential to cease the use of
antibiotics that will save huge health care cost.
In conclusion, PCT appears to be persuasive. It can be regarded as evidenced based
option for rationale use of antibiotics. This narrative review is the eye opener for clinicians to
focus on other infections using PCT for diagnosis of adult emergency department patients.
Further research is required to compare the efficacy of CRP and PCT for its use in diagnosis
of other infections.

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