What Happens If I Fail a Breath or Blood Test in San Antonio?

A Failed Test Is Evidence — Not a Verdict

A BAC result above 0.08 from an Intoxilyzer 9000 or a Bexar County Crime Laboratory blood analysis gives the Bexar County District Attorney’s office a per se intoxication theory under Penal Code §49.01(2)(B). But the test result is only as reliable as the process that produced it. The machine must be maintained. The blood draw must have an unbroken chain of custody. The result must reflect your BAC at the time you were driving. All of these are independently challengeable.

Immediately After a Failed Breath Test in San Antonio

License suspension clock starts. A first failed breath test triggers a 90-day ALR suspension if you do not request a hearing within 15 days of the DIC-25 notice. We file the ALR request the day you retain us.

The criminal case moves forward at Cadena-Reeves. The Bexar County DA’s office will receive the Intoxilyzer 9000 result in discovery. They will use it as the core of their per se theory. But receiving the result is not the end of the defense analysis — it is the beginning of the technical challenge.

Challenging an Intoxilyzer 9000 Breath Test Result

SAPD uses the Intoxilyzer 9000. Every instrument has a maintenance log, calibration record, and error history — all obtainable through Texas open records. We request the complete file on the specific machine used in your test. Common challenge points include:

• Maintenance gaps — missed service within required intervals
• Lapsed operator certification — SAPD officer must hold current Intoxilyzer 9000 certification
• 15-minute observation period — must be documented and uninterrupted
• Partition ratio — fixed 2,100:1 assumption varies 1,700:1 to 2,900:1 between individuals
• Mouth alcohol contamination — belching or regurgitation produces falsely elevated results

See our BAC and breath test defense page for the complete technical analysis.

Challenging a Blood Draw Result at the Bexar County Crime Lab

Blood draws in San Antonio DWI cases are analyzed at the Bexar County Crime Laboratory. The chain of custody from venipuncture through the lab analyst’s report must be documented at every link. Challenge points include phlebotomist qualifications, tube type and preservation, storage conditions, gas chromatograph calibration, and analyst certification. Improper preservation can allow in-vitro fermentation, producing additional ethanol post-collection.

The 0.15 Enhancement

A BAC of 0.15 or above on a first offense elevates the charge from Class B to Class A misdemeanor — $4,000 fine maximum, mandatory ignition interlock on conviction. The same technical challenges apply — but the stakes of successfully suppressing the result are higher.