Labs will rarely volunteer the limits of a test to a private individual — not usually from dishonesty, but because their intake assumes you already know the vocabulary. So ask directly: what panel, exactly? Free or total? On what reporting basis? Has my kind of sample been checked for matrix effects? And are you accredited for this? Five questions, asked before you pay, prevent almost every disappointing lab report an individual receives. This page gives you the questions, the plain-English meaning behind each, and the answers you should expect from OpenChemWorks in Davis, California.
1. "Which amino acids are actually in the panel?"
"Amino acid profile" sounds complete. It almost never is. Panels differ in which amino acids they include, whether ammonia is reported, and how they treat the difficult ones.
Here, the free panel is called AA-1. It covers 19 amino acids plus ammonia, measured by AQC (AccQ-Tag) pre-column derivatization with HPLC-UV — the amino acids are chemically tagged, separated on a column, and measured against a calibrated standard. Cysteine is excluded from AA-1 because it needs a separate workup, called AA-3. Taurine is not part of the routine pitch, and the extended compounds sometimes grouped as AA-2 — GABA, ornithine, citrulline, taurine, and hydroxyproline — are not claimed as routinely included. If a lab quotes you a profile without listing its panel, you do not know what you bought. Ask for the list, in writing.
Why it matters for you: if the one compound you care about is the excluded one, a cheaper full-looking report is worthless. Ask this first.
2. "Is this free, total, or are you blurring the two?"
Free amino acids are the ones already dissolved and available in the food as eaten. Total amino acids include those still bound inside protein, released only when the protein is broken apart. They are different numbers for the same sample, and total is always the larger figure for protein-bound amino acids like glutamate in a protein-rich food.
Free analysis is the AA-1 panel above. Total analysis here, AA-T, hydrolyses the sample in 6 N hydrochloric acid at 110 °C for 24 hours before measurement, and costs $230 per sample. Blends of the two ideas — a lab reporting a hydrolysed result as if it described the food as eaten — produce the most misleading reports individuals receive, especially for glutamate, where "total" can be mistaken for the taste-relevant free amount. Ask which one the quote is for, and make the lab use the words free or total on the quote itself.
3. "On what basis will you report my result?"
A number without a basis is decoration. Basis means the denominator and the form: milligrams per gram of sample, milligrams per 100 grams, milligrams per serving, glutamate as glutamic acid, or glutamate converted to an MSG equivalent — and if MSG, whether anhydrous or monohydrate, which convert differently. Two correct results for one sample can look far apart purely because the basis differs.
Ask for the basis before testing, and ask that the report show the per-analyte results, the basis beside each, and the chromatogram — the instrument trace — behind the numbers. The companion article on reading a lab report works through bases and the MSG conversion step by step. If a lab will not state its basis in advance, that is your answer about the lab.
4. "Has a sample like mine been checked for matrix effects?"
The matrix is everything in your sample besides what is being measured: salt, fat, colour, spice oils, sugars. A strong matrix can suppress or inflate an instrument reading, so a result can be neatly printed and still pulled off true by the sample itself.
The check is called matrix-effect qualification, or spike recovery: a known amount of the analyte is added to your actual sample and the lab measures how much of it is recovered. Ask whether your sample type needs it, especially for dry seasoning blends, dark sauces, and oily or very salty products. Here it is priced per sample and matrix on inquiry; a recent single-sample seasoning project with full matrix-effect qualification was $350. A lab that has never considered the question for your matrix is telling you something. Equally, a lab that insists every simple sample needs the full qualification is selling, not advising — for a simple liquid the standard panel may be sufficient, and you should hear that plainly.
5. "What are you not — and what can I not use this for?"
Few labs lead with their limits, so ask. OpenChemWorks states its own here so you can copy the standard: the lab is not GLP, GMP, or ISO/IEC 17025 accredited; it is currently validating and reserving pilot slots; results are for your own decisions, not regulatory submission; and no turnaround is promised in this article, because none is approved — ask for the current position when you enquire and keep the reply. Single samples are welcome and individuals are accepted, at published prices: AA-1 at $150 per sample for liquids, $180 for powders ($150 plus $30 powder preparation), $150 flat for first-time customers, and $125 per sample at 25 or more samples per month.
If your intended use is a regulatory filing, a retailer specification, or a dispute with a supplier, ask the other party what they will accept before you commission anything. A non-accredited report used hopefully in an accredited context helps no one, and an honest lab will tell you that before taking your money.
Your next step
Copy the five questions into an email to any lab, including this one: info@openchemworks.com. Judge the replies by whether they are specific, written, and willing to state limits. Then decide.
Frequently asked questions
Is it rude to ask a lab these questions?
No. They are the questions a manufacturer's quality manager asks routinely. You are entitled to the same specificity for one sample.
What if a lab will not put prices in writing?
Treat that as a finding. Published prices here exist precisely so an individual can budget before writing.
Do I need all five questions for a simple sample?
Questions 1, 2, and 3 always apply. Question 4 grows in importance as the sample gets saltier, darker, fattier, or more complex. Question 5 always applies if anyone else will rely on the result.
Can I ask about cysteine or taurine specifically?
Yes, and you should if either matters to you. Cysteine needs the separate AA-3 workup; taurine is not pitched as routine here.
References
- OpenChemWorks — Pricing — Published service and pricing copy (2026).
- Waters — Derivatization of Amino Acids Using Waters AccQ-Tag Chemistry — Method background for AQC derivatization and HPLC-UV amino acid analysis.
OpenChemWorks Laboratory · Reviewed by the laboratory director, PhD chemist · Published October 16, 2026