Using Alternate Light Source to Identify Subclinical Bruising

There’s a terrific new article, available electronically ahead of publication that I’d like to highlight this morning. [Ed: okay, I will revise the terrific part, since the authors botch fluorescence vs absorption, or at least qualify my use of it to say that it’s terrific for me, because of the article’s conclusions.] It’s important, because it contributes to the science on using an alternate light source to identify subclinical bruising. The use of ALS for this purpose, particularly in strangulation cases, is one against which I caution folks, because the limited research on the subject hasn’t been particularly (forgive me) illuminating. This study changes that.

Published in the Journal of Forensic Science, Is Fluorescence Under an Alternate Light Source Sufficient to Accurately Diagnose Subclinical Bruising? is the research for which I have been waiting. For one thing, it includes a control group as a comparison, which allows for the ability to examine sensitivity and specificity, a significant limitation of Holbrook & Jackson’s article. Furthermore, it helps outline the appropriate use of ALS in assessing bruising: “The ability of ALS fluorescence to enhance the visualization of a known bruise visible under white light may assist in identifying a clear pattern that is consistent with the reported mechanism of injury.” (p. 5). But because there has been a spectacular push to use this technology to assess bruising without much actual evidence behind it, consider what I think is the most important statement in the entire article:

“…our results demonstrate that more than half of the time, positive fluorescence is something other than a bruise. There is no evidence base, therefore, to support the use of an alternate light source as an independent tool to definitively interpret fluorescence as a sub- clinical bruise (i.e., bruising that is not visible to the naked eye). Given the high false-positive rate in detecting subclinical bruising, it is essential for medical and legal professionals to understand the resulting implications of promoting the use of ALS in a forensic setting.” (p. 5)

This article is worthy of a thorough read. It is not the final word on the topic by any means—it, too has limitations, including a relatively small sample size. However, it is, for me, a good place to finally begin having the conversation. Too much of what has been taught and spoken about on this subject has been based on very little research and quite a bit of conjecture. I have addressed that, to some extent, in my clinical guide on ALS and bruising (now updated), but I’m thrilled to have this article to support my professional skepticism on its widespread adoption for assessing bruising in the clinical setting.

3 replies on “Using Alternate Light Source to Identify Subclinical Bruising”

Hi, with respect to the above post and the quotes from the soon to be published paper on using an ALS for the detection of bruising, it is clear that the authors still do not have a good understanding of the basic science behind using an ALS in this application. There is NO fluorescence involved. It is strictly the absorption and reflection characteristics of chromophores in the pooled blood in the bruise relative to the surrounding tissue that allows you to potentially detect an area that may be a bruise or other ligature or strangulation marks. In our training on the use of an ALS, we discuss the actual science of the absorption properties of the various chromophores, and make it very clear that the use of an ALS alone cannot confirm the presence of a bruise or other mark, but can only add credence to the information being provided by the victim. No detection system at this time can confirm the presence of a bruise.


I agree that the fluoresce vs absorb aspect gets botched here–I don’t know if it’s a sloppy use of language or actual misunderstanding of the science. I will attempt to reach out to the authors for clarification (I do not know them personally). However, the takeaway in this research is critical for me, seeing how many emails I get a month (not to mention conversations I have at trainings and conferences) about people eager to use or already using ALS to identify bruising, along with attorneys wanting to take this type of “evidence” into court. I’m thrilled to hear you are not teaching that ALS can identify subclinical bruising, but I know that is not the consistent message being taught out there.

Thanks for your comment–and for reading FHO.


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