- Course Introduction
- 01: Evidence & DNA
- 02: Forensic Biology
- 03: DNA Extraction & Quantitation
- 04: DNA Amplification
- 05: Amplified DNA Product Separation
- 06: STR Data Analysis & Interpretation
- Data Troubleshooting
- Data Interpretation & Allele Calls
President's DNA Initiative
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Advancing Justice Through DNA Technology
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Advancing Justice Through DNA Technology
DNA Analyst Training
Negative Control(s) & Reagent Blanks
Home > STR Data Analysis & Interpretation > Data Interpretation and Allele Calls > Step 1: Internal Size Standards and Allelic Ladders >Negative Control(s) & Reagent Blanks
Reagent blanks are routinely processed with samples. Laboratories include reagent blanks in the extraction, quantitation, and amplification processes to aid in monitoring potential contamination of reagents and/or supplies. These blank samples should show no DNA pattern other than that of the internal size standard. Negative controls or reagent blanks showing unexplained extraneous DNA could indicate contamination.
Analysts should closely evaluate blank samples, including assessment of peaks under the established threshold. If there is a discernable pattern of allelic activity that cannot be attributed to a spike, pull-up or other artifact, the analyst should troubleshoot the problem and follow the procedures established by the laboratory.
Click here to read more about detecting and preventing contamination in Subject 04, Module 04.
