How to keep a personal BAC log that stays understandable
The most useful BAC log is not the one with the most commentary. It is the one that uses the same fields every time and preserves the source.
For each entry, record the date and time, displayed reading and units, device make or model, a clear display photo, the testing context, and any relevant device or calibration note. Preserve gaps and corrections instead of smoothing them over.
1. Use one repeatable entry format
Consistency makes a log easier to scan and reduces the chance that an important detail appears only on some days. Set the fields once and use them in the same order.
Do not add medical interpretations. The entry should describe the displayed result and the record around it.
- Date and local time
- Displayed reading and displayed units
- Device make and model
- Photo of the complete display
- Short context note
- Device, maintenance, or calibration note when relevant
2. Photograph the display as source material
A readable photograph gives the reviewer the device display you saw. Include the full screen and avoid editing the image. If the device shows an error or ambiguous result, preserve that instead of turning it into a numeric reading.
A photograph does not establish who provided the sample or whether the device was accurate. Label it as a display photo, not independent verification.
3. Record the device without overstating it
Device type matters because alcohol-measurement systems have different intended uses and controls. Keep the make, model, and any manufacturer-recommended maintenance information available.
If you change devices, identify the change in the timeline. Do not merge readings from different devices into a single uninterrupted series without noting the transition.
4. Keep context short and factual
Context can explain why the entry exists: before scheduled parenting time, part of a personal accountability routine, or requested by a professional. It should not become a diary entry that interprets the result.
If a prescribed protocol controls timing or procedure, follow it and record that the entry was made under that protocol without claiming independent compliance.
July 27, 8:04 p.m. Displayed reading: 0.000. Device: [make/model]. Attached: unedited display photo. Context: scheduled personal evening check. No correction.
5. Leave gaps and corrections in place
A gap means no entry was preserved for that point in the sequence. It should not be filled with a later estimate.
If the wrong number or time was entered, add a dated correction and keep the original visible. That history is more useful than a perfect-looking chart with no explanation.
A BAC log documents a sequence of self-recorded readings. It does not turn those readings into monitored tests or medical conclusions.
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.
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