What is QPCR Efficiency and Why Should You Care?
qPCR Efficiency refers to how well a quantitative polymerase chain reaction (qPCR) amplifies DNA. A high-efficiency qPCR ensures that your DNA amplification is accurate and reliable.
If you are in molecular biology, genetics, or any field requiring DNA quantification, a highly efficient qPCR can save you time, resources, and potential headaches. Accurate efficiency leads to better diagnostic results, research outcomes, and advancements in biotechnology.
How to Calculate QPCR Efficiency
The formula is:
[\text{Efficiency} = -1 + 10^{\left(\frac{-1}{\text{Slope}}\right)}]
Steps:
- Find the Slope: Obtain the slope from your qPCR standard curve (typically from your qPCR software)
- Calculate Efficiency: Plug the slope into the formula
Where:
- Efficiency is the qPCR Efficiency (expressed as decimal or percentage)
- Slope is the slope obtained from the qPCR standard curve
Calculation Example
Suppose you have a slope of -3.32 (ideal slope for 100% efficiency):
[\text{Efficiency} = -1 + 10^{\left(\frac{-1}{-3.32}\right)}]
[\text{Efficiency} = -1 + 10^{0.301} = -1 + 2.0 = 1.0 = 100%]
Interpreting Results
| Slope | Efficiency |
|---|---|
| -3.32 | 100% |
| -3.58 | 90% |
| -3.10 | 110% |
- 90-110% efficiency is considered acceptable
- Values outside this range indicate the need for optimization
Common Causes of Low Efficiency
- Suboptimal primer design
- Inhibitors in the sample
- Poor template quality
- Incorrect reaction conditions