The Tick-Borne Encephalitis (TBE) diagnostic criteria calculator evaluates whether a patient meets the criteria for definite or probable TBE infection, based on clinical symptoms, epidemiological exposure, and laboratory test results. The procedure considers the following inputs:

- Clinical Criteria: Presence of symptoms indicating central nervous system inflammation, such as meningitis, meningoencephalitis, encephalomyelitis, or encephaloradiculitis.
- Epidemiological Criteria: Potential exposure scenarios including either a tick bite or stay in an endemic area, or exposure to the same food source as a confirmed TBE case during an outbreak.
- Laboratory Criteria: Results from various laboratory tests for TBE, including detection of TBE-specific antibodies and other markers in serum or clinical specimens.

The calculator evaluates these inputs according to detailed conditions:

1. Clinical Criteria is met if the patient exhibits symptoms of central nervous system inflammation.
2. Epidemiological Criteria can be satisfied by:
   - Exposure from a tick bite or stay in an endemic area.
   - Exposure to unpasteurised dairy products in a common source outbreak with a confirmed TBE case.
3. Laboratory Criteria can be fulfilled by several test results, including:
   - Presence of both TBE-specific IgM and IgG antibodies in serum.
   - Detection of IgM (with or without IgG) in cerebrospinal fluid (CSF).
   - Evidence of seroconversion or a significant increase in TBE-specific IgG antibodies in serum samples.
   - Detection of TBE virus nucleic acid or isolation of the virus from a clinical specimen.

Interpretation of the results is based on the combination of these criteria:

- Definite TBE: If clinical criteria and either of the epidemiological criteria are met, combined with either both IgM and IgG antibodies present in serum or any one of the other specified laboratory findings is present.
- Probable TBE: If clinical criteria and either epidemiological criterion are met, combined with the presence of IgM antibodies in serum.
- Criteria Not Met: If the inputs do not satisfy the conditions for definite or probable TBE.

The ECDC criteria for tick-borne encephalitis (TBE) is a diagnostic tool designed to identify and classify cases of TBE, a viral infectious disease affecting the central nervous system. This tool is particularly useful in endemic areas where the risk of TBE is high, and during outbreaks linked to unpasteurised dairy products, a known transmission route for TBE virus.

The criteria are divided into three categories: clinical, epidemiological, and laboratory. The clinical criteria focus on symptoms indicative of central nervous system inflammation, such as meningitis, meningoencephalitis, encephalomyelitis, and encephaloradiculitis. The epidemiological criteria consider potential exposure to TBE virus, either through a tick bite in an endemic area or consumption of the same food source as a confirmed TBE case during an outbreak. The laboratory criteria involve various tests to detect TBE-specific antibodies or the TBE virus itself in serum or cerebrospinal fluid (CSF).

The final diagnosis is determined by a combination of these criteria. A definite TBE diagnosis is made if the patient exhibits central nervous system inflammation symptoms and has either potential exposure to TBE virus or shared food source with a confirmed case, along with positive laboratory results. A probable TBE diagnosis is made if the patient meets the clinical and epidemiological criteria and has TBE-specific IgM antibodies in serum. If these criteria are not met, the diagnosis of TBE is ruled out. 

This diagnostic tool aids in the early detection and appropriate management of TBE, thereby reducing the risk of severe neurological complications and improving patient outcomes.