What Are the Risks of Measurement Inaccuracy With CTPs?

• CMS/OIG oversight (US wound care, CTP use): Audits focus on utilization patterns and trends, not just claims; inconsistent or erratic wound size changes and measurements just above payment thresholds may trigger scrutiny and potential upcoding concerns.

• Measurement methods: Manual ruler measurements may overestimate wound size by ~27–40%; digital platforms provide calibrated, timestamped, reproducible images; fluorescence/spectral tools add objective data (e.g., bacteria, inflammation) to support documentation.

• Coverage criteria (LCDs): Continued CTP use often requires 10–20% wound reduction over 4–6 weeks; variability (e.g., ±15% manual error) can undermine proof of improvement, emphasizing need for consistent, accurate measurement methods.

Please note: This content is a direct transcript, capturing the authentic conversation without edits. Some language may reflect the flow of live discussion rather than polished text. 

Mr. Nelson is the VP Sales & Marketing for Swift Medical and Founder of the WoundCareFund & Below the Knee.

So what's the risk of inconsistent or inflated measurements? So let's talk about the part nobody likes to discuss. Inconsistency. So we've all seen the headlines over the last probably four to six months, a little beyond that, but the ones that are more fresh. CMS, OIGs, they're definitely paying attention to utilization patterns. So it's not just what is billed, but how the data trends to support what is billed. 
 
So erratic size estimation might be a red flag. Did a wound shrink dramatically one week and then expand the next week. Did it hold steady for a long time and then take a massive greater than 50% reduction in a short period of time? So that might happen in instances. We know that we're going to see erratic behavior in patients as they're healing, but if that becomes the norm, something to watch out for. So that consistency and the accuracy in your measurement can create a red flag that's going to drive someone to take a deeper dive.
 
So overestimation compare. It can be a risk. Especially if wounds are consistently land just above those payment thresholds occasionally. But if every time I do something, I just happen across the line that increases the reimbursement, that might be something that auditors or other people may be looking for. So that overestimation to some people might appear as upcoding. It's not about questioning what people are doing, putting all of our own actions in the eyes of how is this going to be interpreted? Am I really get that level of accuracy that I need?
 
Patterns are going to matter more than individual claims. So the OIG has repeatedly emphasized improper payment risk and skin substitutes. We know they've been looking, are going to continue to look so look at that area just because of the issues that we're all living these days. So they don't just review charts, they review behavior trends. So as your practice and as you're looking at how you're preparing for—we're talking about CTPs, but it could be other modalities—but what are the trends? Where are you consistent? What aspects of your measurement, which becomes the baseline, the standard? Are you as accurate and consistent as you can be? In today's data-driven audit world, inconsistency is right not just a harmless variation. It can be interpreted as a signal. 
 
So that's why I think people just need to be really cautious about driving some significant accuracy around the measurements. But it's also that consistency. You want to be kind of behaving the same. Don't change. I mean, I'm not suggesting people do differently than what they're reviewing of a patient. You're going to get erratic, some changes based on your patient population. But this is getting into, are you consistently just above measuring high? 
 
We're going to get into the next topic here about what are some things that drive some of those overestimations. So technology versus manual measurement. The obvious big question, right? How defensible is your measurement method? So manual ruler-based measurements, a lot of people out there are listening to this and are telling me through, I'm hearing the noise through the internet, how accurate your use of a paper ruler is. So paper rulers are overestimated in size up to 40%. And that's not a SCOT study, that's available information in the public domain anywhere from 27 to 40%. Almost 40% is generally paper rulers or overestimated. So if I'm doing a manual method, really it's critical that you're being as accurate as you can be because now we know that that modality can tend to trend toward the higher size measurement range, which we know in this environment, you just want to be accurate. 
 
So digital platforms, and there are many out there. Now those provide calibrated timestamp stored images that make measurement reproducible and much more auto-defensible. It's objective. It takes the subjectivity out with the paper ruler. Is it curved? Did it get into the blood or the exited of the wound? At what angle was it relative to the position of the wound? If I'm taking a picture, who's taking the picture? How was the information transmitted? So all these variables stack and create that inconsistent measurement that we see with those. So if we know that technology's available, I would be asking everybody, "Why aren’t you using it?" But you want to use the right one, calibrate it, timestamp stored. Things are really going to make your job easier, not replace you, make your job easier. 
 
Spectral is fluorescence, right? Take this even further. So now if I can get an accurate objective measurement, then if I can layer on additional information, is it thermal? Am I looking at a bacterial fluorescent image? So I'm really not only gathering a consistent measurement of the wound image, but now I'm really taking into account, am I seeing inflammation? Am I seeing bacteria form? These things help build, again, that medical necessity story that we're all telling in the chart notes around why it is that you did what you did, not what you did, but the why behind it. 
 
So digital spectral, right? They help you to create that story around supporting medical necessity. They don't create medical necessity. You as the clinician does, but these are tools that really help put you in a much more defensive position around what it is that you're doing. They're going to stand up much stronger to a RAC or a UPIC review. Those are not going to go anywhere. They're tools that are going to be used and we're all going to hear about them more and more. But I think there's the opportunity for some of these tools that'll just help you as the providers be in a much better position for you to ... Again, these tools shouldn't be replacing you, but they should be making your job much easier. 
 
So measurement frequency and treatment continuation. So we talk about the importance of the measurements here. So here's where precision can become mathematical. So, many LCDs, Local Coverage Determinations, so they require measurable improvement, maybe 10 to 20% reduction over a four- to six-week period to justify continued CTP.
 
What is their particular policy? They're going to look for improvement and they're going to be very quantifiable and measured. Now, if I've got a manual measure method that has maybe a plus or minus 15% variability, low into that range. So if I have a plus or minus 15% variability of the method that I'm measuring and I'm trying to prove a 10 to 20% reduction, kind of hard. Math is now stacking up that it's going to be difficult to, without interpretation or without question, be able to document this continued medical necessity. And that's where that consistency method matters. So I want the accuracy, but now we need to be incredibly consistent with the manner in which we're doing this. So the same method, same stats, same debridement timing that prevents the trend line from becoming noise. Again, putting everybody in a much more defensible, much better position for around the medical necessity.
 
So continuation decisions are increasingly data driven. Precision isn't about perfection. It's about credibility. If the auditor's coming in and they're going to, are they really able to understand the reason without questioning it? So accurate, consistent measurement is essential to demonstrate progress and that justify the ongoing therapy.