Reading the Breath Test Printout

At the end of a breath test, the State produces a document called the Breath Alcohol Test Affidavit. To many folks it looks like a form with a number on it. To a forensic lawyer-scientist, it is a map of where the case can be won.

Every line on that affidavit is a place to check the State’s work. Reading it the right way is often where a breath challenge begins.

What the Affidavit Shows

The printout, formally the FDLE Breath Alcohol Test Affidavit, records far more than the result. It logs the air blanks and control tests the machine runs, the breath samples, the time of every step, the instrument’s serial number, the date of the last agency inspection, the time observation began, and the reference cylinder used for the control tests. Each line is a thread to pull. The form looks official and final. It is really a set of claims, every one of which can be tested against the records and the science.

This is the document the State relies on, the FDLE Breath Alcohol Test Affidavit. Read line by line it becomes a list of questions: do the control tests hit the known value, was the reference cylinder in date, do the two subject samples agree, did continuous observation truly cover the time before the test, and what did the form choose not to record.

Reading It Line by Line

The control tests have to hit the known alcohol value, and the reference cylinder behind them has to be in date, both of which live in the inspection and calibration records. The two subject samples have to agree within Florida’s tolerance, which ties to the margin of error. The serial number links the result to a specific instrument with its own history. The time stamps have to square with when continuous observation truly began under the 20-minute rule. And what the form leaves out, your breath temperature for one, matters as much as what it includes.

The Codes That Flag a Bad Test

The Intoxilyzer 8000 prints a short code whenever something goes wrong, and each one points to a defense. SLOPE NOT MET (SNM) means the alcohol level fell instead of leveling off, the signature of mouth alcohol. RFI DETECT (RFI) means radio interference strong enough to corrupt the test. INTERFERENT DETECT (INT) means the two infrared filters disagreed and a substance other than ethanol may have been read. VOLUME NOT MET (VNM) and NO SAMPLE PROVIDED (NSP) mean the breath sample was too small or too short to be reliable. AMBIENT FAIL (AMB) and PURGE FAIL (PUR) mean the chamber did not clear between steps. CONTROL OUTSIDE TOLERANCE means the machine’s own check missed its known value. Each of these flags a problem with the sample or the instrument, and most of them stop the test outright.

The 8000 also keeps a memory. Every test it runs is stored in an archive the state calls COBRA, the Complete Online Breath Archive, which holds up to 150 tests and is downloaded to the Florida Department of Law Enforcement. That archive lets us pull the machine’s recent history and see whether it was throwing these codes for other people near the time it tested you.

Flag	What it means
No Sample Provided	No sample, or one too brief to count
Volume Not Met	Sample under 1.1 liters, marked not reliable
Slope Not Met	The reading did not rise and plateau as a deep-lung sample should
RFI Detect	Radio-frequency interference, which aborts the sample
Interferent Detect	A substance other than ethanol, which aborts the sample
Ambient Fail / Purge Fail	The chamber did not read clean before or after a reading
Control Outside Tolerance	A control reading fell outside its allowed range

Many of these never reach the one-page affidavit. They live in the machine’s electronic record.

Each of these flags opens onto a defense of its own, and each is worth understanding in its own right. A sample marked too small raises the questions covered on our page about volume not met and the 1.1 liter rule. A chamber that would not read clean is the subject of purge failures and chamber contamination. Sequences that stopped early are covered under aborted test sequences, interference under radio-frequency interference, and a control that drifted out of range under inspections versus the machine’s own data. The affidavit rarely shows any of this, which is why reading the full electronic record matters, and why the code on a printout is a starting point rather than the whole story.

What Is Missing

The affidavit does not print everything that shaped the number. There is no breath temperature, no partition ratio, no measurement uncertainty. The machine reports a clean figure and keeps its assumptions to itself. Knowing what is not on the form is part of knowing how to challenge it.

Why This Matters in Your Case

The affidavit is the State’s headline exhibit, admissible as presumptive proof of the result. When you can read it the way the analyst does, and point to what it shows and what it hides, the number stops being the last word. Every page in this section is, in the end, a way of reading that form. Start with the overview or see how we challenge a breath test.

The affidavit captures the numbers and the housekeeping, but the assumptions that most affect accuracy, your temperature and your ratio, never appear on it.

What the Card Cannot Tell You

The affidavit is useful precisely because of what it records and revealing because of what it omits. It does not show your breath temperature, your true partition ratio, the shape of each exhale that bears on mouth alcohol, or the margin of error around the result. A reader who takes the card at face value sees a clean number. A reader who knows what is missing sees the questions the card was never designed to answer, which is where the underlying instrument data and records come in.

Many folks are handed a single page and told it is the result, and I read it as the tip of a much larger record. I go through the affidavit line by line, I decode every flag, and then I pull the electronic data behind it, because the codes on the paper point to failures the summary never spells out. I know what each of these flags means and where it leads, and I follow every one of them, because the difference between a clean test and a troubled one is often written in a three-letter code the State would rather you skip past.

Questions About the Affidavit

What is on an Intoxilyzer 8000 breath test affidavit?

The affidavit records the air blanks and control tests, the breath samples, the reported result, the time of each step, the instrument’s serial number, the date of the last agency inspection, the observation start time, and the reference cylinder used. Each field can be checked against the records.

What is not shown on a breath test result?

The form does not print your breath temperature, the assumed partition ratio, or the measurement uncertainty. Those assumptions shape the number but stay off the affidavit.

Why do two breath samples appear on the form?

Florida requires two samples that agree within a set tolerance. How close they are, and whether they agree, is part of judging the result.

Can the affidavit help my defense?

Yes. Read carefully and matched to the inspection records, the timing, and the science, the form often shows exactly where the result is open to challenge.

Related: the main breath test defense page, how we challenge a breath test, and the calibration and inspection records.

This page is general information, not legal advice, and it does not create an attorney-client relationship. The figure above is an illustration modeled on the FDLE breath test affidavit, not a real test record. Breath testing in Florida is governed by Fla. Stat. 316.1932 and 316.1934 and the Florida Administrative Code chapter 11D-8. Procedures and rules change, and every case turns on its own facts. Past results do not guarantee a similar outcome.