The Yale iGEM Team participated in the 2018 Interlab Study. As part of the study, we helped to reduce lab-to-lab variability in fluorescence measurements by normalizing to absolute cell counts and CFUs (instead of OD). To do this, we first calibrated our plate reader's measurements by doing the following: (1) Using LUDOX CL-X as a reference point for OD600 measurements (2) Creating a particle standard curve using microspheres (3) Creating a fluorescence standard curve using fluorescein. Next, transformed chemically competent E. coli DH5a with the plasmids specified in the protocol. We then picked colonies and grew them overnight. The next day, we measured absorbance at 600nm and fluorescence of all of our samples as specified. Lastly, we calibrated our OD600 measurements to CFUs by following the protocol involving plating multiple dilutions of cultures at specified OD600 values.
Overall, our experience with the Interlab study went fairly smoothly. However, it would have been nice to have a more clarity about whether we were supposed to submit our raw data measurements OR whether we were supposed to submit normalized data (using our calibration measurements). In the end, we decided that it would be best to submit our raw data since our calibration measurements were included in the data submission. Otherwise, we encountered no problems with the protocols and were able to follow the rationale behind each step as well.