Mycoplasma Testing Search Clinical Trials Find a Researcher Order a Test This procedure tests mouse ES cell culture supernatants for the presence of contaminating mycoplasma. Mouse ES cells imported from other institutions are required to pass mycoplasma testing when entering the Core. In addition, this service can be requested by the investigator following gene targeting of mouse ES cells. In addition, investigators can provide supernatants from their own cell cultures for screening. The media should be collected after at least 48h in continuous culture with the cells being tested. It should be stored at 4C and tested for mycoplasma within 5d. The presence of antibiotics in the media is acceptable, although this may mask low levels of mycoplasma contamination in the culture.