The foolishness of Numeric Health Measures for the Microbiome

Today I was asked if the numbers shown on various sights like the one below, ” if this result is correlated with the severity of the patient?”. The answer is No. The usual reason that such numbers appear on sites is to satisfy customers asking for such numbers. Simple, easy to understand number.

Businesses want to make customers happy — so they literally cook-up a number to show on their reports. There is no research supporting any of the magical numbers that I have seen. Some one put together some numeric formula to generate the numbers.

For Biomesight, the logic is shown on the page with the right display

If you sum up the values for each dial, you get the total. When you view the percentage, it is not so obvious: 100%, 69%, 88%, 85% looks like a complex formula is being used.

Analogy: Give me a Health Measure for a Person

The microbiome is very much like a person. How would you create a single value for a person?

  • Probiotics –> Income
  • Commensals –> Savings
  • Pathobionts –> Debts
  • Diversity –> Health?
    • Married and marriage status
    • Chronic Conditions
    • Health Status
    • Height
    • Weight
    • Gender
    • etc

Would a person with no debt, good savings, a low income and married with 5 kids be a higher or lower measure than someone with moderate debt, high income, small savings and no relationships?

Are there any studies?

What about the ratios used in the literature?

  • Bacteroides/Bifidobacterium Ratio
  • Bacteroides/Clostridium Ratio
  • Blautia/Bacteroides Ratio
  • Firmicutes/Bacteroidetes Ratio 
  • Prevotella/Bacteroides Ratio

Well, the sample that I am looking at have 43%ile, 98%ile, 7.2%ile, 58%ile and 19%ile. The numbers are all over the place!

We also have two studies:

Their latest study states: ” accuracy of 80% in distinguishing healthy (no disease) from non-healthy (diseased)” So 1 in five times, they will misclassify a healthy person as having a disease.

An example of the algorithm being used is below.


This is just trying to determine if the person is healthy or not — nothing about severity.

My approach is simple, I simply flagged the bacteria deemed to be unhealthy. Just list them.

How to use it:

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