Icterus in blood samples is due to an excess amount of bilirubin. Since bilirubin is photosensitive, will sunlight be able to remove or reduce the icterus effect in a sample? and if it can be removed, can the sample still be used for testing?
Good day Mr. Gonzales,
That is a good question. Sunlight and room light will definitely have an effect on icteric specimens. Bilirubin is a photosensitive substance that is present in moderate to large amounts on icteric samples. Moreover, bilirubin is degraded through the process of photoisomerization and photooxidation upon exposure to light (Sofronescu et al., 2012). The rate of photolytic activity on bilirubin depends on the duration of light exposure. From this premise, it can be inferred that light can degrade a certain amount of bilirubin in the sample. However, according to Sofronescu et al. (2012), the sample needs to be exposed for longer periods; at least 8 to 24 hours, for a significant change to happen. Unfortunately, it wouldn’t be practical to perform in clinical chemistry laboratories given the short turnaround time of tests and the heavy workload of a usual clinical chemistry laboratory.
Reference:
Sofronescu, A. G., Loebs, T., & Zhu, Y. (2012). Effects of temperature and light on the stability of bilirubin in plasma samples. Clinica Chimica Acta, 413(3–4), 463–466. https://doi.org/10.1016/j.cca.2011.10.036
Good Day, Mr. Gonzales.
Expressing appreciation for your insightful question. Exposing clinical chemistry samples, especially icteric blood samples with elevated bilirubin levels, to sunlight or room light is strongly discouraged due to several key concerns. Light exposure can induce chemical changes in bilirubin, potentially leading to inaccurate test results. Prolonged light exposure can also degrade various components in the sample, compromising its composition and test validity. Additionally, there is a risk of introducing environmental contaminants during light exposure, further impacting result accuracy. While it's true that light can degrade bilirubin, this process requires extended exposure, typically 8 to 24 hours, making it impractical for clinical chemistry laboratories with quick turnaround times and heavy workloads (Sofronescu et al., 2012). To maintain the integrity and accuracy of clinical tests, adhering to established laboratory protocols and consulting experienced professionals for alternative, scientifically validated methods to mitigate bilirubin interference without relying on light exposure is essential.
Reference:
Sofronescu, A. G., Loebs, T., & Zhu, Y. (2012). Effects of temperature and light on the stability of bilirubin in plasma samples. Clinica Chimica Acta, 413(3–4), 463–466. https://doi.org/10.1016/j.cca.2011.10.036
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