A color-change kit on the side of the road is a guess, not proof. The lab work that follows, and the weight that turns possession into trafficking, can both be tested.
Call 904-383-7448The roadside drug field test that justified an arrest is well documented for false positives, turning the same color for ordinary substances as it does for real contraband. The confirmatory lab analysis is better but not beyond question, and the weight that drives a trafficking charge under section 893.13, Florida Statutes, and chapter 893 depends on how the substance was measured. Each step is a place to test the State's proof. Call 904-383-7448.
The inexpensive kits officers carry are presumptive tests: a chemical changes color, and the officer reads that change as a likely drug. The trouble is that the same color can appear for things that are not drugs at all. Over the years these kits have flagged ordinary household substances, common foods, and harmless powders as controlled substances, and people have been arrested on the strength of a reaction that a real laboratory would never have called positive. A field test result is a reason for further testing, not proof of guilt, and treating it as proof is exactly the mistake a defense should expose.
To prove at trial what a substance actually is, the State generally relies on confirmatory analysis at a crime laboratory rather than the roadside kit. That analysis is more reliable, but it is not automatic and it is not beyond challenge. The instruments have to be calibrated, the analyst has to follow the method, and the sample has to be the same one seized at the scene, which is why the chain of custody matters from the moment of the stop. Under the Confrontation Clause, the analyst who did the work can be called to the stand and cross-examined; a signed report should not be allowed to testify on its own.
In drug cases, weight is everything. A small difference can move a case from simple possession under section 893.13, Florida Statutes, into trafficking territory, where the mandatory minimum sentences begin. So how the substance was weighed becomes a live issue. Did the measurement include packaging, moisture, or non-controlled filler? Was the whole mixture counted, or only the controlled portion the law actually reaches? Was the scale reliable and the procedure documented? When a threshold can decide whether someone faces probation or a mandatory prison term, the measurement deserves to be examined down to the gram.
A drug case often looks airtight until each step is pulled apart: the false-positive risk in the field test, the assumptions baked into the lab work, the gaps in the chain of custody, and the way the weight was determined. None of these guarantees a result — it depends on the facts — but together they give the defense real ground to stand on. Graham Syfert concentrates on challenging this kind of scientific evidence and has taught other attorneys how to do the same.
Related: back to challenging scientific evidence; see also breath test challenges and DNA evidence challenges. If you are facing a charge, start with Jacksonville drug crime defense.
They are presumptive, not conclusive. The inexpensive color-change kits used on the roadside have well-documented false positives, reacting to ordinary substances as if they were contraband. A field test, by itself, is a reason to question the arrest rather than proof of guilt.
To prove the identity of a controlled substance at trial, the State generally relies on confirmatory lab analysis, not the roadside kit. That lab work, the analyst's method, and the chain of custody are all testable, and the analyst can be cross-examined under the Confrontation Clause.
Weight drives whether a case is simple possession under section 893.13, Florida Statutes, or trafficking with mandatory minimum penalties. How the substance was weighed, what was included in the total, and whether packaging or non-controlled material was counted can all be challenged, because the threshold can decide the entire outcome.
The call is free and confidential. Whether it is a traffic citation or a felony, the sooner a defense begins, the more can be done. Graham W. Syfert answers his own phone.
Call 904-383-7448Graham W. Syfert, Esq., P.A. · Jacksonville, Florida
Serving Duval, Clay, Nassau, and St. Johns Counties