BCA Breath Alcohol Lab is Mislabeling Controls on the DMT!

Posted On October 23, 2023 Charles Ramsay

At Ramsay Law, we function as independent auditors for the state testing labs. And we’ve found that the BCA breath alcohol lab has made a MASSIVE mistake. They are at it again—using suspect practices with their breath machines. 

When the BCA sends a DMT breath machine out to the field, they install a cylinder with a known amount of alcohol. This is the known reference value that the DMT is measured against to ensure it’s measuring accurately.


While looking at recent case files, I noticed that the certificate of analysis for the control sample is analyzed out to 4 digits, like this: 0.0795. 

When an officer receives a new DMT, they are instructed to run a control change. This tells the DMT the concentration of the reference cylinder. And since the DMT only uses 3 digits, you’d expect the officer to enter 0.079 as the reference number.

But instead, the BCA uses conventional rounding and rounds up to 0.080. They relabel the control by rounding it up! So, even if the DMT measures perfectly at 0.0795, it will always report 0.079. This makes it look like the instrument is measuring low when, in reality, it isn’t!

The BCA shouldn’t be rounding up controls to make it look like the DMT is running low. Instead, they must use the same rounding method as the DMT.

This is a massive problem.

For years, I’ve been suspicious about why the DMT breath machine seems to measure the control sample lower than it should. You’d expect the DMT sometimes to measure low, sometimes high, and other times right on target. 

But I’ve cracked the code, and it isn’t pretty.


If the BCA is mislabeling the controls they send out to the field, they’re likely doing the same thing when calibrating the DMT in the lab. This means that they’re calibrating the DMT to measure every citizen's breath sample to read higher than it should!

This isn’t the first time we’ve found problems at the BCA lab; here are some other problems we’ve found:


This error is another example of why you need a law firm that knows the science and the law.

If you’ve been a victim of the state’s shoddy science, call Ramsay Law. We look at every aspect of your case to ensure that no stone goes unturned.

We’re the only law firm in the state with a lawyer board-certified in DWI law (recognized by the ABA, not the MSBA).

Call us to discuss your case. Contact Ramsay Law at 651-604-0000.

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