Please select the eligibility criteria that correspond to the clinical trial below.
Title: Procalcitonin Guided Antibiotic Therapy and Hospitalisation in Patients With Lower Respiratory Tract Infections: The "ProHOSP" Study
Brief Summary: The aim of this study is to test if procalcitonin (PCT) guided antibiotic stewardship in patients with lower respiratory tract infection (LRTI) will be non-inferior, with at worst a 7.5% higher combined failure rate, as compared to standard care practice (current guidelines for LRTI) with reduced total antibiotic (AB) use and hospitalization rate and duration, respectively.


Options:
A: Inclusion Criteria:

1. Patients 18 years of age or older, admitted from the community or a nursing home with acute (i.e., at least 1 day but less than 28 days) LRTI as the main diagnosis consisting of having at least two of the following:

   * new or increased respiratory signs or symptoms (i.e., cough, sputum production, dyspnea, auscultatory findings of abnormal breath sounds and rales, pleuritic chest pain) with or without inflammatory signs (core body temperature \> 38.0° C, leukocyte count \> 10 or \< 4 x 10\^9 cells L-1).
   * CAP is defined by the presence of LRTI along with a new or increased infiltrate on chest radiograph. Severity scores of CAP (pneumonia severity index \[PSI\] and CURB-65) will be calculated.
   * COPD is defined by post-bronchodilator spirometric criteria according to the GOLD-guidelines as a FEV1/FVC ratio below 70% and the severity categorized into mild (FEV1 \<= 80% of predicted), moderate (50% \>= FEV1 \< 80%), severe (30% \>= FEV1 \< 50%) and very severe (FEV1 \< 30%), respectively. Severity of acute exacerbations of COPD will be graded as proposed. Acute bronchitis is defined as LRTI in the absence of an underlying lung disease or focal chest signs and infiltrates on chest X-ray, respectively. Patients who are on admission judged as having an LRTI but have another final diagnosis, will be classified as "others".
2. Ability to understand verbal and written instructions and informed consent.

Exclusion Criteria:

1. Patients unable to give written informed consent, e.g. with severe dementia or patients not understanding German (or other local language) and no translation (e.g. family members) available.
2. Patients with active intravenous drug use.
3. Severe immunosuppression (e.g. patients infected with human immunodeficiency virus infection and a CD4 count below 350 x 10\^9/L, patients on immunosuppressive therapy after solid organ transplantation and neutropenic patients with present neutrophil count \< 500 x 10\^9/L and patients under chemotherapy with neutrophils 500-1000 x 10\^9/L with an expected decrease to values \< 500 x 10\^9/L); patients with cystic fibrosis, infection with M. tuberculosis, L. pneumophila, Listeria spp. hospital stay within 14 days of inclusion.
4. Accompanying chronic (e.g. osteomyelitis), abscess (e.g. brain, pleural empyema) infection or endocarditis.
5. Terminal and very severe medical co-morbidity where death is imminent or has to be expected in the current hospitalization (e.g. due to malignancy, cardiac, renal or hepatic failure, comfort therapy).
B: Inclusion Criteria:

* 18 years or older
* Informed consent
* Respiratory tract infection based on the clinical judgement of the primary care physician

Exclusion Criteria:

* Antibiotic pretreatment in previous 14 days
* Portal hypertension
* Major surgeries or multiple trauma which require hospitalization, in previous 4 weeks
* Autoimmune disease and systemic diseases (lupus erythematodes, wegener´s disease)
* Peritoneal dialysis
* Acute treated or recently operated medullary c-cell-carcinoma, SCLC, carcinoid
* Other inflammatory diseases (e.g. urinary tract infection, pyelonephritis, pancreatitis
C: Inclusion Criteria:

Fulfilment of all of the following three criteria:

1. Male or female, aged \> 18 years of age.
2. Admitted to the participating Intensive Care Units (ICUs) at the following hospitals: Hvidovre Hospital, Bispebjerg Hospital, Amager Hospital, Herlev Hospital, Glostrup Hospital, and Gentofte Hospital
3. Ability to understand and provide written informed consent to participate in this trial; or ability to understand and provide oral informed consent in the presence of at least one impartial witness who should sign and personally date the consent form; or the subject's legally acceptable representative can understand and provide written informed consent if the subject is not capable of this because of the present mental or physical condition of the subject.

Exclusion Criteria:

A subject will NOT be eligible for inclusion in this trial if any of the following criteria apply:

1. Subjects with known hyperbilirubinaemia (\> 0.4 mg/ml) or hypertriglyceridaemia (\> 10 g/l) since this can interfere with measurements. If subjects with unknown status on these points are included and have PCT measurements, the measuring equipment will detect these conditions.
2. Subjects suffering from a blood disorder, where daily sampling of 7 ml of blood for a maximum of 28 days (210 ml distributed on 28 days) will be an inconvenience or a potential risk, which could compromise the safety of the subject.
3. Subjects who are pregnant or breast feeding

The a priori probability of surviving with the normal recommended diagnostics and treatment with the presently available means to detect infections and, on the other hand, the normal diagnostics and treatment together with daily procalcitonin measurements and prompt clinical reaction should be equal.
D: Inclusion Criteria:

* written informed consent
* all types of respiratory tract infection according to investigator´s diagnosis

Exclusion Criteria:

* pretreatment with antibiotics in the past 2 weeks
* portal hypertension
* Major surgeries or multiple trauma which require hospitalization, in previous 4 weeks
* Autoimmune disease and systemic diseases (lupus erythematodes, wegener´s disease)
* Peritoneal dialysis
* Acute treated or recently operated medullary c-cell-carcinoma, SCLC, carcinoid
* Other inflammatory diseases (e.g. urinary tract infection, pyelonephritis, pancreatitis

Answer: A