What does TCID mean in MEDICAL

Tissue-Culture Infectious Dose (TCID) is a laboratory method used to measure the infectivity of a virus or other infectious agent. It involves diluting the infectious agent in a series of dilutions and then adding each dilution to a monolayer of cells in a tissue culture plate. The TCID is the dilution at which 50% of the cell monolayers show signs of infection.

TCID is calculated using the Reed-Muench method, which is a statistical method that uses the proportion of infected cells at each dilution to determine the dilution at which 50% of the cells are infected. The TCID is expressed as the number of infectious units per milliliter (IU/mL).

TCID is an important measure of viral infectivity and can be used for a variety of purposes, including:

• Quantifying the amount of virus in a sample
• Comparing the infectivity of different viruses
• Evaluating the effectiveness of antiviral drugs
• Studying the pathogenesis of viral infections

TCID has some limitations, including:

• It can be time-consuming and labor-intensive to perform.
• It is not always accurate for viruses that have a slow replication cycle.
• It can be affected by the type of cell culture used.

There are a number of alternative methods for measuring viral infectivity, including:

• Plaque assay
• Focus-forming assay
• Immunofluorescence assay
• Real-time PCR