Wednesday, December 18, 2019

Toward Better Doctor Patient Communication through Normalized Test Results

I was recently visiting an ill friend in the hospital.  The Doctors would come in occasionally and tell him that his INR was such and such, and his Hemoglobin was so and so.  Now my friend has been dealing with his condition for some time, and there were numbers that he understood, but for many of them I had no idea what the number meant, whether it was high or low, and if it was high or low, how much of a concern it was.

While I was sitting in the room, it occurred to me that a standard system for communicating the numbers could be set up.  The idea briefly is that every number would be Normalized for the particular patient, at least so far as to account for age, weight, gender and so on.  A normal result would be 100, and anything between 90 and 110 would be ok, or cause for very little concern.  Up to 120 and down to 80, needs attention.  Above 140 or below 60, very serious concern.

It is already a common practice to include this sort of information with lab results, the (almost meaningless) measured number will be given, and then a color code, or the words "high" or "low" appended as necessary.  If normalized numbers were used instead, all of this would be unnecessary, and communication would be much improved.

It is true that many people have learned the meaning of various numbers.  I was told that Diabetics for example, are very familiar with the blood sugar numbers, and know immediately what the reported number means.  Likewise we all learn early what a normal temperature is, and what a fever is, though it is interesting that Fahrenheit wanted his scale to be something like what I am proposing, where it would be obvious if you had a fever, because 100 was the normal temperature.

Apparently his methods or apparatus were insufficient, and we therefore have a normal temperature, as measured in degrees Fahrenheit, that is almost 100, but far enough away that 100 is a mild fever.

My proposal would require some re-learning, in that 100 would be, as Fahrenheit intended, a normal temperature, but we could see a number of 104 as a very mild fever, rather than a pretty severe one as now.  It would not be until an indicated 120 or so that a fever would be indicated, as one standard deviation above the mean.  I'm not an expert in any of this, but my understanding is that a temperature below normal is is more concerning that one above, but a normalized scale would take care of that, as 80 would be one standard deviation below normal, whatever measured temperature that corresponds too.

In truth, for temperature we perhaps don't need this, but it is a good example for how the numbers would map, precisely because we are already familiar with it.

One final thought: it would be wise to have a convention for using these numbers, perhaps prefixing them with N both in text and speech, as in "Your bp is N100/100", to let someone know it is exactly normal.

Disclaimer:  I am not a physician,  I have not yet done all the work to build this into useful system, and I have not engaged a large number of people to determine if they also think it would be helpful.  My lovely wife thinks it is a terrific idea, but she is perhaps biased.