Usage of DNA Fingerprinting Technology to Check Sample Error and Contamination in Molecular Laboratories

Abstract

Sample identification error is a severe medical error in clinical molecular diagnostic laboratories, which can lead to reporting the wrong results for the patient involved. Sample contamination can also lead to incorrect test reports. Avoiding sample identification error and sample contamination could be life-saving. Sample switch and sample contamination could happen on laboratory bench works, especially when pipetting into multi-well plates. It is difficult to realize such errors during laboratory bench work. Laboratory staff may not be aware of such an error when it happens. DNA fingerprinting technology can be used to determine sample identity and subsequently identify sample switch and sample contamination in the laboratory. Our laboratory has explored the usage of this technology in our quality control process and successfully established that DNA fingerprinting can be used to monitor sample switch and sample contamination in next-generation sequencing and BCR/ABL1 real-time PCR bench work.

Keywords: DNA fingerprint; quality control; sample contamination; sample error; sample switch.

Figure 1

This figure consists of the electropherograms from multiple samples of the same category to protect the DNA fingerprint of any one sample. (A) is the DNA fingerprint from the NGS library. The arrow indicates a non-specific peak. (B) is the DNA fingerprint from the original sample.

Figure 2

This figure consists of the electropherograms from multiple samples of the same category to protect the DNA fingerprint of any one sample. (A) is the DNA fingerprint from the BCR/ABL1 real-time PCR reaction mixture. (B) is the DNA fingerprint from the original sample.

Figure 3

This figure consists of the electropherograms from multiple samples of the same category to protect the DNA fingerprint of any one sample. (A) is the DNA fingerprint from a common reagent. (B) is the DNA fingerprint from the BCR/ABL1 real-time PCR reaction mixture with a high BCR/ABL1 level.

Figure 4

This figure consists of the electropherograms from multiple samples of the same category to protect the DNA fingerprint of any one sample. The DNA from two individuals were mixed with one of them contributing 5% of total DNA as a surrogate of contaminating DNA. Such ‘contaminating’ DNA was detected as indicated by the low peaks (red arrows). Please note that D13S317 is a non-informative marker for this mixture. The two low peaks of D21S11 (green arrows) can be considered as stutters.