Preventing contamination and error

Next to your health and safety and the health and safety of those around you, your concern should be to eliminate the possibility of contamination and error in all the work that you do in the lab.

Believe it or not, there are some simple behavioral traits that you can use to help reduce both error and contamination in the lab. They are:

  • BE PATIENT. Never rush any procedure. You are more likely to make a mistake that will cause either an error or contamination when you are feeling the pressure to finish your work and leave. Always allow yourself ample time for all the steps you need to carry out.
  • BE ORGANIZED. Have a clear understanding of what it is you need to do and write your plan out in your notebook before you begin lab work. A good time to outline your work in your notebook is while you are waiting for your reagents to thaw.
  • PAY ATTENTION. When you are handling DNA tubes or PCR products, this is not a time to be talking with others in the lab or thinking about what to eat for dinner. Be very careful to always transfer the correct DNA or PCR product to its respective tube. If you make a mistake, STOP. Notice what it is you have done and, if it is a mix-up you can fix or correct in your notebook, do so. Otherwise, START OVER.

Other precautions to follow to reduce contamination:

  • Wipe down your bench space before and after use with 10% bleach.
  • Do not transfer any lab supplies from the Sequencing lab into either the DNA Extraction or PCR Set-up labs (certain exceptions apply).
  • Spin down all tubes (reagents and DNAs) and plates before using.
  • Label all tubes and plates well.
  • Always take an aliquot of a stock solution to work with.
  • Always use your own reagents and aliquots.
  • Keep tubes, solution containers, and tip boxes closed whenever you are not using them.
  • For all PCRs, always run a NO DNA NEGATIVE CONTROL.
  • When handling strips or plates of PCR products, be very careful when removing and replacing caps. Always spin first. Remember that even an aerosol amount of PCR product can contain many, many copies of DNA.