Insurance companies and defense lawyers often go straight to a machine's paperwork when they want to challenge test results, arguing that missing entries, late checks, or sloppy records make the numbers unreliable. A calibration log is the written or digital record showing when a testing device was checked, adjusted, serviced, or verified for accuracy. You see these logs with breath-testing machines, blood-testing equipment, drug screens, and other devices that need regular quality control.

Practically, the log can help prove whether a machine was working properly when a sample was tested. If the entries show the device was out of range, overdue for maintenance, or handled by someone without the right training, that can weaken the value of the test result. On the other hand, a complete log may support the other side's claim that the equipment was functioning normally. That makes it a key piece of evidence, especially when a case turns on a lab number or a breath result.

For an injury claim, ask for the calibration log early along with maintenance records, chain of custody documents, and lab procedures. In Idaho, timing matters because personal injury claims are generally subject to a 2-year statute of limitations under Idaho Code section 5-219. If a crash involved heavy truck traffic or a serious trauma case, preserving testing records quickly can matter just as much as preserving the vehicle or medical chart.