A simple method for recording and analyzing serological data.

Titration endpoints from any 2-fold dilution series represent either true or modified base-2 logarithms and can be recorded conveniently by tube or dilution number. The simple arithmetic mean of titers thus expressed can be easily converted to geometric mean titer (GMT) by use of a table of antilogarithms, which is presented. This approach not only facilitates the handling of large volumes of data but also simplifies GMT calculation.