Personal BAC log vs. monitored alcohol testing: what is the difference?

A personal BAC log is created and controlled by the user. A monitored program may control identity checks, timing, device selection, observation, calibration, chain of custody, missed-test rules, and direct reporting. The two should not be described as equivalent.

1. Who controls the test?

In a personal log, the user generally chooses when to test, which device to use, what context to record, and whether to share the result.

A monitored program may choose the device, testing window, procedure, identity method, retest rules, and recipient. That outside control is a central difference—not a small feature.

2. How is identity handled?

A self-recorded display photo does not independently establish who supplied the sample. A monitored system may use observation, video, account controls, biometric checks, or another program-specific method.

Identity controls vary by program. Do not infer them from the fact that a device is connected to an app.

3. How are the device and procedure controlled?

NHTSA distinguishes alcohol screening devices, evidential breath devices, ignition interlocks, and calibration equipment. Formal programs may specify approved devices, maintenance, calibration, and operating procedures.

A home device can still be useful for personal recordkeeping, but the user’s photo and note do not create the quality controls of an evidential or supervised program.

4. What happens when a test is missed?

In a personal log, a missing entry is a visible gap. In a formal program, a missed testing window may have a defined consequence or reporting rule.

Never label a gap as a failed test—or as harmless—unless the governing program defines it that way. Record the gap and follow the program’s instructions.

5. When can a personal log still be useful?

A personal log can support a private accountability habit, preserve context before a formal program begins or after it ends, or provide supplemental records when a professional wants them.

Its value depends on honest framing. Describe it as a self-recorded chronology with visible limitations, not monitored compliance.

If someone else sets the testing terms, their protocol controls. Notarus can preserve your record; it does not redefine the protocol.

Sources and further reading

These primary resources support the general boundaries and terminology in this guide. They do not turn the article into individualized legal, medical, or treatment advice.

• NHTSA: Alcohol Measurement Devices
• NHTSA: Alcohol Measurement Devices and program controls

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