How does lipemia interfere with photometric assays, and what methods can mitigate this issue?

• A. Lipemic samples scatter and absorb light, leading to inaccuracies; mitigation includes ultracentrifugation, dilution, or using assays less affected by turbidity or alternative detection methods like chemiluminescence.
• B. Lipemia interference is limited to spectrophotometric assays only; not photometric.
• C. Lipemia does not affect any assays.
• D. Lipemia is always corrected by adding more sample.

Answer: (A)

Lipemia causes turbidity in a sample because lipid droplets scatter and can absorb light. In photometric assays that rely on measuring light transmitted through the sample and the color change produced by a reaction, this turbidity adds background signal and distorts the amount of light reaching the detector. The result is biased readings that can be falsely high or low, depending on the assay and wavelength used.

To address this, you can remove or reduce the lipids before testing, or use methods that aren’t as affected by turbidity. Practical approaches include ultracentrifugation to clear chylomicrons, diluting the sample to lessen turbidity, or choosing an assay format that is less sensitive to turbidity. Alternatively, switching to detection methods like chemiluminescence (which is less impacted by sample turbidity) or other lipid-tolerant assays can mitigate the interference.