🌱 Gut Health & Absorption

What this panel can settle, and by what logic

Eleven markers, none of which touches the gut directly. What they settle is whether absorption is failing, which is a pattern question rather than a single result.

1. Several deficiencies together is the finding, not any one of them. Low Ferritin with low Vitamin B12, low Folate, Serum, low Vitamin D (25-Hydroxy) and low Zinc, Plasma in one person is a malabsorption pattern; any one of them alone is usually diet, blood loss or sunlight Zheng 2023. That is the discrimination the breadth of this panel buys.
2. The Complete Blood Count (CBC) with Differential indices are the cheapest clue on the list. A microcytic picture points at iron, a macrocytic one at B12 or folate — and a normal mean cell volume in someone deficient in both is the classic mixed picture that hides celiac disease, because the two errors cancel Datta Mitra 2026.
3. Methylmalonic Acid (MMA) beside Vitamin B12 separates a low number from a real deficiency, since methylmalonic acid only accumulates once the B12-dependent step has stalled Harrington 2024 — which matters here because terminal ileal disease produces exactly this.
4. hs-CRP (High-Sensitivity C-Reactive Protein) and ESR (Sed Rate) are doing two jobs at once. They raise the possibility of inflammatory bowel disease, and they are what make the ferritin readable, since inflammation inflates it independently of stores Luo 2023 Cancado 2025.

What it cannot settle, and what would

It carries no celiac serology, which is the single commonest diagnosis it is bought to find. The test is tissue transglutaminase IgA with a total IgA, and it is the recommended first-line investigation Rubio-Tapia 2023. It is not on this panel. Worse, the timing is destructible: you must still be eating gluten, and a few weeks of a gluten-free diet before testing produces a false negative that then takes a formal gluten challenge to undo Rubio-Tapia 2023.

It cannot separate inflammatory bowel disease from irritable bowel syndrome. The test that does is fecal calprotectin, which pooled to a sensitivity of 0.93 and a specificity of 0.96 in adults with suspected inflammatory bowel disease van Rheenen 2010. It is a stool test and costs a fraction of this panel.

It cannot see the lumen or the mucosa. Bacterial overgrowth is assessed by breath testing, lactose and fructose intolerance the same way, Helicobacter pylori by breath or stool antigen, and celiac disease is confirmed on duodenal biopsy Rubio-Tapia 2023. Nothing here images or samples the bowel.

And a low Ferritin in a man or a postmenopausal woman is a gastroenterology referral, not a supplement. The panel tells you the stores are empty; it cannot distinguish poor intake from slow gastrointestinal blood loss, and only one of those is treated with iron Cancado 2025.

Draw conditions that decide whether the money is wasted

One instruction here is worth more than the panel itself, and it is about a test the panel does not contain.

1. Do not start a gluten-free diet before you test. If celiac disease is on your mind, keep eating gluten until the serology and, if needed, the biopsy are done — going gluten-free first invalidates both and forces a formal challenge to get an answer Rubio-Tapia 2023.
2. Stop supplements for 3 to 7 days and iron for 5 to 7. Circulating micronutrient concentrations follow recent intake closely, so a supplemented panel measures the morning stack and misses the malabsorption you are looking for Zheng 2023; serum iron tracks the last tablet while Ferritin tracks the store.
3. Fast 9 to 12 hours and draw the Zinc, Plasma in the morning. Plasma zinc falls after a meal, drifts across the day and falls again with inflammation Ceballos-Rasgado 2024, so a non-fasted afternoon zinc is the version most likely to produce a deficiency that is not there.
4. Not within 2 weeks of an infection. Illness raises hs-CRP (High-Sensitivity C-Reactive Protein) and ESR (Sed Rate), which is the pattern you are trying to interpret, and inflates ferritin at the same time Luo 2023.

How you would know it answered your question, and what each pattern means next

Four patterns, and what each is worth spending on next.

• Three or more deficiencies together: stop replacing them one at a time. Ask for tissue transglutaminase IgA with a total IgA, while still eating gluten, and a gastroenterology opinion Rubio-Tapia 2023.
• Raised hs-CRP (High-Sensitivity C-Reactive Protein) or ESR (Sed Rate) with diarrhea or blood: the next test is fecal calprotectin, not a repeat of this panel van Rheenen 2010. Retest bloods only after that result.
• Isolated low Ferritin with a normal Complete Blood Count (CBC) with Differential: treat, then retest at 12 weeks, because stores refill over months Cancado 2025. A second fall within 6 months means the iron is going somewhere and needs investigating rather than replacing.
• Low Vitamin B12 with a raised Methylmalonic Acid (MMA) and a normal Folate, Serum: think terminal ileum or intrinsic factor rather than diet. Recheck MMA at 4 weeks after replacement, since it responds to correction rather than to the last dose Harrington 2024.

Sources read for these sections

• Rubio-Tapia A, et al. American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease. American Journal of Gastroenterology 2023 · PMID 36602836
• van Rheenen PF, Van de Vijver E, Fidler V. Faecal calprotectin for screening of patients with suspected inflammatory bowel disease: diagnostic meta-analysis. BMJ 2010 · PMID 20634346
• Harrington DJ. The application and interpretation of laboratory biomarkers for the evaluation of vitamin B12 status. Annals of Clinical Biochemistry 2024 · PMID 39367523
• Cancado RD. Defining Global Thresholds for Serum Ferritin: A Challenging Mission in Establishing the Iron Deficiency Diagnosis in This Era of Striving for Health Equity. Diagnostics (Basel) 2025 · PMID 39941219
• Luo H, et al. A Practical Guide to Adjust Micronutrient Biomarkers for Inflammation Using the BRINDA Method. Journal of Nutrition 2023 · PMID 36792034
• Ceballos-Rasgado M, et al. Methods of Assessment of Zinc Status in Humans: An Updated Review and Meta-analysis. Nutrition Reviews 2024 · PMID 38917458
• Zheng J, et al. Biomarkers of Micronutrients and Phytonutrients and Their Application in Epidemiological Studies. Nutrients 2023 · PMID 36839326
• Datta Mitra A, et al. Unusual Micronutrient Deficiencies as Causes of Anemia. Nutrients 2026 · PMID 41754181