Once the sample is received at our laboratory in Auckland, we need to extract the DNA from the blood. This is done by spinning the sample at high speeds and at a low temperature, once completed the blood sample separates into several layers.
The top layer now present in the tube is made up of a substance called plasma, this contains the DNA we require. We extract this out of the sample tube, separate enough to test and then store any excess plasma at -80 degrees Celsius.
DNA contained in the plasma is required to go through a process to remove any unwanted substances and cellular debris, allowing a pure sample of DNA to be collected.
Once the DNA is collected, a process is undertaken to prepare the strands of DNA for a process known as sequencing. This involves more purification steps and modifications of the DNA to allow each patient’s DNA to be identified as belonging solely to that person.
Once DNA has been prepared it is ready for sequencing. This involves the DNA being read in order from start to finish, as you would read a book. Once sequenced, if any abnormal DNA is present, it can be identified. The process of identifying abnormalities by reading the patient’s DNA is done using algorithms and specialised computers/software.