You’ve had the blood test. TSH normal. CBC normal. Maybe a vitamin D that came back “low-ish” and got a shrug. You left with the strong impression that nothing is wrong, and yet you can’t remember what you walked into the kitchen for and you’re asleep by half past eight.
The gap between “no abnormality detected on this panel” and “you are well” is where a great many San Antonio patients get stranded. A standard panel is a narrow window. It wasn’t designed to explain fatigue.
This article sets out exactly how Dr. Bronwen Martin, DC, IFMCP and Dr. Andy Martin, MD investigate these symptoms — step by step, so you can judge whether it’s more thorough than what you’ve already had.
Step One: A History Long Enough to Be Useful
The single highest-yield diagnostic tool for fatigue and cognitive symptoms isn’t a test. It’s time.
Our initial appointment runs 60 to 90 minutes, and most of it is questions. Not “how long have you been tired,” but when precisely it started, what else was happening that month, whether it came on over days or years, whether it’s worse in the morning or after eating, whether it improves on holiday, whether anyone in your family has autoimmune disease.
We build a timeline: illnesses, antibiotic courses, pregnancies, house moves, water damage, major stressors, diet changes, new medications. Patterns emerge from that timeline that no panel picks up. Post-viral onset looks different from gradual metabolic decline, which looks different from an exposure event.
If the last time a clinician asked you an open question was some years ago, a free 15-minute consultation is a reasonable place to start.
Step Two: The Metabolic and Nutritional Layer
Energy production is biochemistry. Several common deficiencies produce exactly the symptom picture people describe, and several sit inside “normal” reference ranges that are wider than optimal function requires.
Iron and ferritin. Ferritin can sit in the low-normal range while symptomatic iron deficiency is present, particularly in menstruating women. This is one of the most frequently missed causes of fatigue and cognitive fog we encounter.
B12 and folate. Functional B12 deficiency can exist with serum levels in range, which is why methylmalonic acid and homocysteine add value.
Vitamin D. Widely tested, less often actually repleted to a target. The NIH Office of Dietary Supplements publishes the evidence review.
Blood sugar regulation. Fasting insulin alongside glucose and HbA1c. Insulin resistance produces post-meal energy crashes and cognitive dulling long before glucose becomes abnormal — and fasting insulin is rarely ordered in routine care.
Magnesium, zinc, and B-complex status, assessed against symptoms rather than in isolation.
Step Three: The Hormonal and Thyroid Layer
A TSH alone is a screening test, not a thyroid assessment. We look at free T4, free T3, reverse T3, and TPO and thyroglobulin antibodies. Antibodies can be elevated for years before TSH shifts — meaning autoimmune thyroid disease is often present and detectable well before conventional criteria are met. The American Thyroid Association covers the standard interpretation. More on our thyroid work.
For sex hormones, timing matters as much as the numbers. Testing on day 3 versus day 21 of a cycle answers different questions. In perimenopause, single-point testing can be actively misleading because levels fluctuate widely — history often outweighs the lab.
We assess cortisol rhythm across the day rather than at a single morning point, because the shape of the curve carries information a spot value doesn’t. We use that data descriptively. We don’t use the “adrenal fatigue” label, which lacks endocrinological validation, and we’ll explain the distinction if you ask. See hormonal health.
Step Four: The Inflammatory and Gut Layer
Chronic low-grade inflammation is strongly associated with fatigue and cognitive symptoms. We measure hs-CRP, and where the history suggests it, we look further.
The gut is investigated when symptoms, history, or inflammatory markers point there — not reflexively. Comprehensive stool analysis can identify pathogens, digestive insufficiency, and inflammatory markers like calprotectin. It cannot tell you your ideal microbiome, and we don’t pretend otherwise. Where celiac disease is plausible, serology comes first. Our gut health page has more.
Step Five: The Environmental and Exposure Layer
This layer is routinely skipped, and in Texas it shouldn’t be. Humidity, storm damage, and flooding across the state mean water-damaged buildings are common, and mould exposure can present as fatigue, brain fog, and unexplained inflammation. The EPA provides guidance on indoor mould.
We ask about your home and workplace: leaks, flooding history, visible growth, whether symptoms improve when you’re away. We ask about occupational exposures, well water, renovation work, and new furnishings. Where the history is suggestive, we test — and we’re clear that no test is worth much if ongoing exposure isn’t addressed first.
Step Six: Sleep, Movement, and Load
We screen for obstructive sleep apnoea, which is common, underdiagnosed, and produces textbook brain fog and fatigue. If the screen is positive, you need a sleep study and a sleep physician, not a supplement protocol — and we’ll refer.
We assess circadian pattern, shift work, activity levels, deconditioning, and whether exertion produces disproportionate payback the following day. That last question matters: post-exertional malaise changes the picture substantially and rules out standard graded exercise advice.
Step Seven: Deciding What Actually Needs Treating
Investigation without prioritisation just produces a longer list. Once results are in, we identify which findings are most likely driving your symptoms, address those first, and re-measure.
We also decide what belongs elsewhere. Suspected sleep apnoea, a concerning neurological sign, a positive autoimmune screen needing rheumatology — these get referred. Dr. Andy Martin’s MD training means conventional referral is a normal part of the pathway, not a last resort. The full process is on how we work and our brain health page.
Frequently Asked Questions
Q: What tests should I ask for if I’ve been told my labs are normal?
A: A reasonable starting request is a full thyroid panel including free T3 and antibodies, ferritin rather than haemoglobin alone, B12 with methylmalonic acid, vitamin D, fasting insulin alongside glucose and HbA1c, and hs-CRP. Many patients find some of these were simply never ordered. If your physician declines, that’s worth a conversation about why — there may be a good reason, or it may be habit.
Q: How long does the investigation take for San Antonio patients?
A: Typically 3 to 5 weeks from first appointment to a full picture. The initial consultation happens within days, blood draws are arranged at a Quest or LabCorp location near you in San Antonio, specialty kits ship to your home, and most results return within 2 to 3 weeks. We then review everything together in a dedicated results appointment rather than emailing you a PDF and leaving you to interpret it.
Q: Could my brain fog and fatigue be one problem or several?
A: Usually several, layered. It’s common to find, for instance, low ferritin plus subclinical thyroid autoimmunity plus poor sleep quality — none individually dramatic, but cumulatively disabling. This is precisely why single-cause thinking fails in these presentations, and why we investigate across systems rather than stopping at the first abnormal result.
Q: Do I need to stop my current medications before testing?
A: Generally no, and you should never stop prescribed medication without speaking to the prescriber. Some medications do affect specific results — biotin supplements interfere with thyroid assays, for example, and proton pump inhibitors affect B12 status. We’ll review your full medication and supplement list beforehand and advise on anything that needs timing adjustment.
