Near-Fatal High-Severity Bug Report

I’ve worked on countless gaming products in my career. 

I was involved in multiple XboxLive updates … and shipped code in Windows Vista for that matter. Yup, I’ve encountered lots of bugs.

I’ve had weeks lost and countless days ruined because of bugs. Software bugs. Hardware bugs. Whole features rendered unusable because of bugs. Furious partners. Revenues lost. 

This bug was by far the most crushing one I’ve ever encountered in my entire life.

Priority: 0 
Severity: 1
Filed: 1:04AM CDT

From a game design perspective, the worst game bugs are the ones where the player is making progress in the game and then a game bug forces the player into the ‘lose’ state even though it’s not the player’s fault. This makes for the worst kind of player frustration - the kind that results in television screens broken from game controllers being thrown at them. 

It’s 9:30pm. 5’s blood sugar has been going up continuously since she fell asleep - currently very high at 320. Probably her body still digesting carbohydrates from her dinner.

It’s been 3 hours since her last short-acting insulin dose, so now it’s time for us to give her a ‘correction’ injection. 2 units of insulin should drop her blood sugar by 200 points, bringing her from 320 to 120 (within her target range of 80-150). 

You know what? That graph looks ever-so-slightly more linear than usual. Maybe it’s worth double-checking with a finger prick?

Lancet: POP! 

Daughter: OWWWWW! 

Glucometer: 169

Parents: What…. The…. @#*$%!?!?!!?!

It was a hardware bug on her Dexcom CGM sensor. Her actual blood glucose is 169, not 320. 

If we had given her 2 Units of insulin it would have dropped her blood sugar by 200 points. Our daughter, now asleep, would have slipped into a diabetic coma, or worse. Mom and I would have just gone back to bed not realizing anything was wrong. The CGM wouldn't have alarmed. It wasn’t working. 

...The moment you realize that if you had just done exactly what the endocrinologists told you to do based on what her glucose monitor said, you could have killed your kid while you all slept. 

You rip out her current sensor and replace it with another $200 sensor you bought at Walgreens. 

• Call the endocrine team.
  • They say ‘call Dexcom’
    • Call Dexcom tech support. They’ll send you a free replacement (woohoo!). 

Now it’s 1am. 

You’re 5 days in. 

You were seconds away from accidentally killing your own kid. 

Good luck trying to fall asleep.