Saliva vs. Blood for DNA Genetic Analysis
In this article, we explore the use of saliva vs blood for DNA Genetic Analysis.
| Feature | Saliva | Blood |
| Invasiveness | Non-invasive; easy, self-collection | Invasive; requires trained personnel, needles |
| DNA Yield | Lower yield | Higher yield |
| DNA Purity | Comparable purity to blood | Comparable purity to saliva |
| Genotyping Accuracy | High concordance (>97%); slightly lower call rates on some platforms | High concordance (>97%); higher call rates |
| Contamination Risk | More prone to contamination (bacteria, food) | Less prone to contamination |
| Suitability | Adequate for most genetic tests; not all complex/rare marker tests | Suitable for all types of genetic tests |
| Convenience | Can be collected at home; higher compliance | Requires clinic visit; lower compliance |
| Cost | Lower total cost; no need for phlebotomist | Higher cost; requires trained staff |
| Storage/Transport | Stable at room temperature; easy shipping | Needs cold chain for long-term storage |
Key Points
- Accuracy and Quality: For most genetic analyses, saliva and blood yield highly concordant results, with minimal differences in DNA quality and genotyping accuracy. However, blood samples tend to have higher genotyping call rates and more amplifiable human DNA.
- DNA Yield: Blood provides significantly more DNA per sample than saliva (up to 10x more), but saliva usually yields enough DNA for standard genotyping and sequencing needs.
- Contamination: Saliva samples are more susceptible to contamination from bacteria and food, which can affect certain tests.
- Convenience and Compliance: Saliva collection is non-invasive, can be done at home, and leads to much higher donor compliance rates. Blood draws require trained personnel and are less convenient.
- Cost and Logistics: Saliva collection is less costly overall, especially when considering the need for phlebotomists, clinic visits, and cold-chain storage for blood.
- Suitability: While saliva is suitable for most genetic tests, some complex or rare marker analyses may still require blood due to higher DNA yield and purity.
Summary
Both saliva and blood are reliable sources for DNA genetic analysis. Blood provides higher DNA yield and slightly better genotyping performance, but saliva offers comparable accuracy for most purposes, with major advantages in convenience, compliance, and cost-effectiveness. Saliva is especially advantageous for large-scale studies, remote sampling, and situations where non-invasiveness is critical.
Have questions about your DNA or RNA extraction projects? Talk to AutoGen. We’re always happy to help you make the best decisions for your project needs.