Inconsistent absorbance readings between replicate wells with coefficient of variation >15%. Visual inspection may reveal bubbles present in wells, particularly when using detergent-containing solutions.
Common Causes
1Solutions containing detergents are especially susceptible to bubble formation
2Rapid or forceful addition of reagents to wells introduces air
3Bubbles remaining in wells interfere with optical reading path
4Multi-channel pipettors may trap air when dispensing detergent solutions
Solutions
1Ensure no bubbles are present prior to reading the plate by visual inspection
2Gently add solutions to the wells to minimize turbulence and air incorporation
3Pop bubbles by touching them with a dry pipette tip before reading
4Allow plate to stand 1-2 minutes after reagent addition for bubbles to dissipate