The present invention provides methods and compositions for the in situ growth, freezing and testing of cultured cells. In particular, the present invention provides methods and compositions for the long-term preservation of cells in ready-to-use formats for testing. In addition, the present invention provides rapid and easy to use means to diagnose viral and other infections. Furthermore, the present invention provides easy to use means to grow and store cells in situ for testing methods. Indeed, the present invention makes viral, chlamydial and other diagnostic methods accessible to small laboratories, including those without cell culture capabilities.