There’s SO MUCH research relevant to the chronic hypophosphatemia community these days that I can’t keep up. Some of it is repetitive and doesn’t add much, I think, and I’ll share some of those links another day, just in case there’s something you’ll find useful in them, but there’s also a good bit of research that produces data that’s sorely needed to back up the patient experience.
Way back in the early 2000s when I was moderating the XLH Network’s listserv, I saw a large number of comments about how a patient’s diagnosis was delayed because the blood lab used the wrong reference range for what was a normal phosphorus level in kids. It was particularly problematic when the patient was a spontaneous case, rather than an inherited one, since parents who themselves have XLH might know that the pediatric normal is higher than adult normal, but parents who hadn’t even heard of XLH before wouldn’t have any reason to question the lab results.
So we frequently posted reminders on the listserv for parents/caregivers to double-check lab results to make sure the correct reference range was used. We knew it was an issue, and we knew, from personal experience that using the wrong range happened, but what we did not know was exactly how often it happened. And without those numbers, it was impossible to advocate for better practices by labs and clinicians who relied on the labs for the reference ranges without understanding them.
Now we have numbers! In “Inadequate pediatric reference ranges impede the diagnosis of X-linked hypophosphatemia and hypophosphatasia in Austria,” researchers found that out of about twenty labs contacted by the researchers, only an appalling eighteen percent (yes, 18, not 80) used pediatric reference ranges, rather than adult ranges.
EIGHTEEN PERCENT!
Note that the labs got the actual phosphorus levels in the test sample reasonably correct, but by using the wrong reference ranges, they failed to label the results as abnormal. This is catastrophic when diagnosing a rare disorder, since it’s not uncommon for the treating physician to be someone who is not particularly familiar with the rare disorder and therefore doesn’t know the appropriate normal ranges personally, so they rely on the lab’s information.
There are, of course, limitations to this study. For one thing, it was done in a relatively small country (Austria’s population is approximately nine million (as compared to e.g., over three hundred million in the US, and over eighty million in Germany), so it might be argued that a larger sample is needed. I would love to see a wider sampling done across Europe and the US, but I wouldn’t be at all surprised to see similar results wherever the study is replicated.
In the meantime, patient groups should, as the article suggests, be working with scientists and politicians to:
- Raise awareness in laboratory medicine societies and federal health legislation to develop national recommendations for pediatric-specific reference ranges.
- Link public [and private] health insurance reimbursement to quality standards for pediatric sample reference ranges.
- Implement a publicly available white-list of institutes for critical parameters, including standardized pediatric reference ranges, at national and European levels
Note that I edited the second suggestion to add private health insurance, which is not a significant option in Austria, but is the main option in the U.S.
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Please note that the author is a well-read patient, not a doctor, and is not offering medical or legal advice.
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