If you’ve researched functional medicine in San Antonio, you’ve probably noticed something uncomfortable. Some practices talk about their lab panels as if every result is definitive. Others dismiss the entire category as pseudoscience. Neither position is honest.
The truthful answer is that functional medicine testing spans a wide range of scientific maturity. Some tests are the same validated assays your primary care doctor orders, simply interpreted against narrower reference ranges. Others are useful pattern-finding tools that shouldn’t be treated as diagnostic. And a few are marketed far beyond what the evidence supports.
At Modern Functional Medicine, Dr. Bronwen Martin, DC, IFMCP and Dr. Andy Martin, MD think patients deserve to know which is which before they spend money. This guide explains what the research actually shows.
Why Test Quality Varies So Much in Functional Medicine
Conventional diagnostic tests go through a long validation process: establishing that the test measures what it claims, reproduces results consistently, and predicts a clinical outcome that matters.
Many specialty lab tests skip parts of that pathway. They’re sold as “wellness” panels rather than diagnostics, which means the regulatory bar is lower. That doesn’t automatically make them worthless. It does mean the burden falls on the clinician to know each test’s limitations and to avoid treating a colourful report as a diagnosis.
Our position is straightforward. A test earns its place in your workup only if the result would change what we do next. If it wouldn’t, we don’t order it.
Not sure whether the testing you’ve been offered elsewhere is worth it? A free 15-minute consultation is a reasonable place to ask that question before you commit.
Which Functional Medicine Tests Have the Strongest Evidence?
Several tests we use routinely are well validated and widely accepted in conventional medicine. The functional difference is usually in how comprehensively we order them and how we interpret borderline results.
Comprehensive thyroid panels. TSH, free T4, free T3, reverse T3, and thyroid antibodies are all standard, reliable assays. The American Thyroid Association publishes guidance on their use. Ordering the full panel rather than TSH alone isn’t controversial science — it’s simply more complete than a typical seven-minute appointment allows.
Metabolic and inflammatory markers. Fasting insulin, HbA1c, hs-CRP, homocysteine, and a full lipid particle panel are validated markers with substantial outcome literature behind them.
Nutrient status testing. Serum vitamin D, ferritin, B12, folate, magnesium (RBC), and zinc are established assays. The NIH Office of Dietary Supplements maintains evidence reviews for each.
Celiac and coeliac-adjacent serology. tTG-IgA and related markers are validated, and identifying celiac disease genuinely changes management.
Breath testing for SIBO. Hydrogen and methane breath testing has real evidence behind it, though sensitivity and specificity are imperfect and results need clinical correlation rather than automatic treatment.
Which Tests Are Useful but Frequently Overinterpreted?
This is the category where honesty matters most, because these tests are heavily marketed across Texas and beyond.
Comprehensive stool analysis and microbiome panels. These can identify pathogens, parasites, digestive insufficiency, and inflammatory markers like calprotectin — all clinically meaningful. What they cannot yet do is tell you your “ideal” microbiome. Human microbiome science, including work catalogued through the NIH Human Microbiome Project, has not established a single healthy reference composition. Anyone who reads your bacterial ratios like a horoscope is ahead of the evidence. We use these panels for what they reliably detect, and we say so.
IgG food sensitivity panels. These are among the most contested tests in the field. The American Academy of Allergy, Asthma & Immunology has been explicit that IgG antibodies to food may simply reflect exposure rather than pathology, and does not recommend the panels for diagnosing food sensitivity. We’re candid about this. Where a panel is used at all, we treat it as a hypothesis-generator for a structured elimination and reintroduction trial — which remains the actual gold standard — not as a list of foods to avoid forever.
Salivary and dried urine hormone testing. Four-point salivary cortisol gives genuinely useful information about diurnal rhythm that a single morning blood draw misses. Dried urine metabolite testing adds detail on how hormones are processed. Both are reasonable tools. Neither supports the “adrenal fatigue” framing you’ll see marketed, which lacks endocrinological validation. We use the data; we don’t use the label. You can read more about how this fits our hormonal health work.
Organic acids testing. Individual markers are measurable and some are informative. The interpretive frameworks layered on top vary considerably in rigour.
Which Tests Do We Not Use?
We don’t order hair mineral analysis for nutrient assessment, given consistent reproducibility problems between labs. We’re cautious about provoked heavy metal testing, which reliably produces elevated results whether or not meaningful body burden exists. And we don’t use tests where the marketing claim has clearly outrun the published literature.
Declining to order something is also a clinical decision. It saves you money and prevents treatment aimed at a finding that may not be real.
How This Changes What Happens in Your Appointment
Testing informs a plan. It doesn’t replace one. A thorough history frequently tells us more than any panel, which is why our initial appointments run long — often 60 to 90 minutes.
For every test we recommend, we’ll tell you three things: what it measures, how confident we are in the result, and what we’d do differently depending on the outcome. If we can’t answer the third question, the test isn’t worth running.
When findings point toward something requiring conventional specialist care — suspected inflammatory bowel disease, a concerning thyroid nodule, an autoimmune presentation needing rheumatology — we say so and coordinate rather than compete. Dr. Andy Martin’s MD training means conventional referral pathways are part of how we practise, not an admission of failure.
You can see the full process on our how we work page.
Want a second opinion on lab work you’ve already paid for? Bring it. We’re happy to tell you what it does and doesn’t show.
Frequently Asked Questions
Q: Are functional medicine tests covered by insurance in Texas?
A: Coverage varies significantly. Standard blood panels ordered through conventional labs — thyroid, metabolic, nutrient markers — are often at least partially covered under your existing plan. Specialty panels from functional labs are usually self-pay, though costs are typically transparent and quoted upfront. Some patients use HSA or FSA funds. We’ll always tell you the likely cost before ordering anything, and we’ll tell you honestly if we think a particular test isn’t worth the expense in your situation.
Q: Do I need to be in Houston to have functional medicine testing done?
A: No. We’re based in Houston, Texas and see patients across San Antonio, Austin, Dallas, and 32 states through HIPAA-secure telehealth. Blood draws are arranged at a lab near you — San Antonio has extensive Quest and LabCorp coverage — and specialty test kits are mailed to your home. You collect the sample and post it directly to the lab.
Q: How many tests will I actually need?
A: Fewer than you might expect. Most patients start with a comprehensive blood panel plus one or two targeted specialty tests chosen based on their history and symptoms. Ordering a large battery upfront generates data that’s expensive, sometimes contradictory, and often not actionable. We’d rather test in stages, guided by what we learn.
Q: What if my test results come back normal?
A: Normal results are informative. They rule things out, they narrow the differential, and sometimes they redirect us toward factors that testing doesn’t capture well — sleep, stress physiology, movement, or environmental exposure. Normal labs never mean your symptoms aren’t real. It means we keep looking.
