Procalcitonin for the diagnosis of bacterial infections and guidance of antibiotic treatment in patients with non-specific complaints

A method for diagnosing a bacterial infection in a patient comprising the steps of:

• (i) detecting and quantifying the level of a Procalcitonin (PCT), or a fragment thereof having at least 12 amino acids (collectively, PCT analyte) in a bodily fluid sample from said patient,
• wherein the detection and quantitation comprises a PCT detection assay with a functional assay sensitivity of below 0.06 ng/mL, comprising contacting said PCT analyte with a capture molecule that specifically binds to the PCT analyte to form a detectable PCT analyte:capture molecule complex, and detecting the complex,
• wherein said patient does not have a primary disease, and who is presented to the emergency department with one or more non-specific complaints said selected from the group consisting of “not feeling well,” “feeling weak,” “feeling exhausted,” “being tired or sleepy,” “feeling dizzy,” having a lack of appetite, being unable to cope with usual daily activities, and the patient being unable to recall why they were sent to the emergency department, and with the proviso that the patient did not present to the emergency department with any complaints specific to infection;
• (ii) comparing the thus-detected level of PCT analyte in said sample to a predetermined threshold level of between 0.02 ng/mL and 0.25 ng/mL;
• and
• (iii) diagnosing whether said patient has a bacterial infection or not by comparing said determined PCT level with said predetermined threshold level;
• wherein the patient is diagnosed with a bacterial infection if the PCT analyte level is higher than the predetermined threshold level, and
• whereby the diagnosis is used to determine whether to prescribe antibiotic treatment for the patient diagnosed with a bacterial infection.