Understanding BCR-ABL1 IS Calibration
What is IS Calibration?
The International Scale (IS) for BCR-ABL1 is like a universal language for laboratories worldwide. Think of it as converting different currencies to a single standard - just as you might convert pounds, euros, and dollars to a single currency for comparison.
Why is it Important?
- Enables consistent patient monitoring across different laboratories
- Critical for treatment decisions, especially when considering therapy cessation
- Required for participation in clinical trials and research studies
Cross NCP et al. Development and evaluation of a secondary reference panel for BCR-ABL1 quantification on the International Scale. Leukemia (2016) 30, 1844-1852.
When Results Exceed Expected Values
If your calibration results deviate significantly from expected values:
- Check PCR Efficiency:
- Optimal efficiency should be between 0.9 and 1.1
- Efficiency ratios between BCR-ABL1 and control genes should be ~1
- Suboptimal efficiency often indicates PCR optimization issues
- Verify Sample Input:
- Use recommended RNA/cDNA input amounts
- Check for PCR inhibition
- Consider testing a dilution series
- Actions to Take:
- Optimize PCR conditions (primers, temperatures, reagents)
- Validate with additional control samples
- Consider repeat testing with adjusted conditions
- Document all troubleshooting steps