The results are substantial and reliable
While the study offered clear results, it was not without fault. One of the limitations of the study was the lack of appropriate serum samples, meaning that the serum samples could have been left unprocessed for some time, or were not collected in the special tubes required for handling blood serum. In some other cases, extra DNA from white blood cells were found to have leaked into the blood serum, contaminating some specimens and making them more difficult to read.
Widschwendter notes that even with these contaminations and limitations, the results of the study are too clear to dismiss. He wrote that in spite of the large contamination of the population-based samples with normal DNA, the team could observe a clear tumor DNA signal in what ordinarily would have been a much stronger and clearer signal. This serves to show that the marker is reliable beyond small amounts of contamination.