Friday, August 13, 2021

Decoding Why Ancestors Died

Thanks to the Summer 2021 issue of American Ancestors from the New England Historic Genealogical Society, I have a new tool for analyzing death certificates  filed in the 20th century.

Genealogist Hallie Borstel wrote about the International Classification of Diseases code, either three or four numbers added to a death cert to categorize the cause of death.

Look at the Wood ancestor's death cert above. See the three digit code 131 in the red circle? That's the ICD.

I looked up 131 in the 1929 ICD listing for causes of death, and see the classification is chronic nephritis.

The doctor's written cause of death on this particular cert is: "cardio-vascular renal disease."

Not exactly the same as code 131, but very closely related. If the doctor's handwriting had been illegible, the ICD code would have given me insight into cause of death.

To use the ICD, look for the most recent version adopted before the ancestor's death. In this example, the ancestor died in 1936, so I used the 1929 version (excerpt shown above). If she had died in 1939, I would have used the 1938 version. 

Another tool in my genealogical tool kit! 


  1. Interesting. I don't remember ever seeing this code but I'll be looking for it now!

  2. Your tip about checking the year makes sense. I didn't realize that medical codes keep updating. Thanks.

  3. What a fabulous tool! Thanks for sharing!!!