If standard blood work keeps telling you everything is fine while your body tells you something different — the Organic Acids Test is worth knowing about. Dr. Sherri explains what it measures, who it's for, and why she has used it for over 10 years.
One of the most common and most frustrating clinical situations I see is this: a patient walks in carrying a stack of bloodwork — complete metabolic panel, thyroid, CBC, maybe a basic hormone panel — all flagged normal, all within reference range. And they have been exhausted for two years. Or their digestion has been a mess for as long as they can remember. Or they've had unexplained anxiety or brain fog or chronic fatigue that no one has been able to explain.
They've been told they're fine. They don't feel fine.
This is not a rare presentation. It's one of the most common things I see in functional nutrition practice. And the reason standard labs miss it is not that the doctors ordering them are wrong — it's that standard labs were designed to catch disease, not to assess how well your metabolic machinery is actually running.
There is a meaningful difference between "no diagnosable pathology" and "optimal function." Standard blood work is very good at the first one. It does almost nothing for the second.
The Organic Acids Test — the OAT — lives in that gap. It's the tool I reach for when someone's symptoms don't match their labs, when complex chronic complaints have gone unexplained, and when I need a window into what is actually happening at the cellular level.
The Organic Acids Test is a simple at-home urine test. You collect a first-morning urine sample, mail it to the lab, and get back a comprehensive report on your metabolic function. That's it. No blood draw, no doctor's office visit to collect the sample, no fasting requirements beyond the overnight fast you'd naturally have before your first morning urine.
The term "organic acids" refers to byproducts of metabolic processes in the body. When cells are burning fuel, synthesizing nutrients, managing bacteria in the gut, or running neurotransmitter pathways, they produce metabolic byproducts that end up in your urine. The OAT measures those byproducts and uses them to draw conclusions about how those processes are functioning.
It's a functional test. Not a disease marker. A measure of how efficiently — or inefficiently — your body is doing the things it's supposed to do every day.
Here's a breakdown of the major categories the OAT gives us information on:
Mitochondria are where your cells produce energy. When mitochondrial function is compromised — by nutrient deficiencies, oxidative stress, or chronic illness — you feel it as fatigue that doesn't resolve with rest. The OAT includes markers that directly reflect how efficiently your mitochondria are working. This is something standard labs essentially never look at.
A standard blood test for B12 tells you how much B12 is circulating in your blood. It does not tell you whether your cells are actually using it. The OAT's organic acid markers reflect functional B vitamin status — whether B12, B6, biotin, and other B vitamins are getting into the metabolic pathways where they need to work. A person can have a normal serum B12 and still show functional B12 insufficiency on the OAT. I see this regularly.
Dysbiosis — an imbalance of gut bacteria or an overgrowth of yeast — produces specific byproducts that show up in urine. The OAT includes markers for both bacterial and yeast-related metabolites. For patients with unexplained fatigue, brain fog, bloating, or mood symptoms, these markers often point me in a direction that no standard GI workup had identified.
The OAT includes markers for dopamine and serotonin pathways. Not the neurotransmitters themselves — those don't show up in urine in a meaningful way — but the metabolic byproducts of their breakdown, which reflect how actively those pathways are running. For patients with mood instability, anxiety, or depression that hasn't responded to what should be working, this can be illuminating.
The OAT includes markers for glutathione production and oxidative stress. Oxidative stress is a major driver of fatigue, inflammation, and cellular damage — and it's something standard labs don't measure at all. When I see elevated oxidative stress markers on an OAT alongside the fatigue and inflammatory symptoms a patient is describing, I know where to focus.
I'll let my own words speak here, because I've said this to patients for over a decade and it still captures it exactly.
Let me be concrete about the clinical picture the OAT gives me that I cannot get from standard bloodwork.
Nutrient deficiencies at the cellular level, not just in circulation. The difference between serum B12 and functional B12 is one example. The same principle applies to other B vitamins, CoQ10 (via mitochondrial markers), and antioxidant capacity. Standard labs measure what's in your blood. The OAT measures what your cells are actually doing with it.
Gut dysbiosis signatures without invasive testing. Identifying yeast or bacterial overgrowth typically involves stool testing or more invasive GI workup. The OAT's urinary markers often give me a meaningful first signal — not a full GI map, but enough to know whether dysbiosis is likely contributing to the symptom picture and whether a deeper investigation is warranted.
The metabolic fingerprint of fatigue. Fatigue is one of the most under-investigated symptoms in conventional medicine because the standard workup rarely finds a cause. The OAT's mitochondrial markers, B vitamin markers, and oxidative stress indicators often show me exactly what's driving it. Whether it's poor mitochondrial efficiency, high oxidative stress, functional B12 insufficiency, or a combination — the OAT can show the mechanism when everything else just says "results normal."
A rational basis for targeted supplementation. This is something I feel strongly about. Walking into a supplement store and choosing products based on general wellness claims is not nutrition medicine. The OAT lets me build a protocol that is specifically targeted to this patient's actual deficits — not a generic protocol, but a targeted one. That changes outcomes.
I have been using the OAT as a staple part of my nutrition practice for over a decade. I've ordered it on hundreds of patients, and the patterns I see most consistently are worth naming.
Functional B vitamin insufficiencies are extremely common — particularly B12 and B6. Patients who eat well, supplement regularly, and have normal serum levels. The OAT shows their cells aren't using those vitamins effectively. Often this traces back to methylation issues, gut absorption problems, or the metabolic demands of chronic stress burning through B vitamins faster than the body can replenish them.
Mitochondrial stress markers are elevated in nearly every patient presenting with true chronic fatigue — not tiredness, but the kind of exhaustion that doesn't improve with rest. This finding changes my entire approach because I'm now working with the energy production system directly rather than just addressing the symptoms.
Yeast markers show up far more often than people expect, especially in patients with longstanding digestive symptoms, brain fog, sugar cravings, or a history of repeated antibiotic use. The OAT doesn't tell me the full story on gut health, but it tells me enough to know when gut work needs to be central to the protocol.
Elevated oxidative stress markers appear consistently in patients with inflammatory conditions — autoimmune presentations, chronic pain, skin conditions — even when their standard inflammatory markers like CRP or ESR look acceptable. The OAT is showing me cellular oxidative burden before it's registering on the standard tests most doctors use to assess inflammation.
After 10 years, I still find it one of the most informative single tests I can order. Not because it answers every question — it doesn't — but because it asks the right ones. The ones that actually explain why someone feels the way they do.
If this sounds like it might speak to what you're dealing with, I'm glad to talk through whether it makes sense for you. That's exactly what the inquiry call is there for.