Important Iron, B12 & Malabsorption

Abstract

This is currently an occult-blood / iron-monitoring / low-normal-B12 problem, not proven iron-deficiency anemia or a broad malabsorption syndrome. The completed clean-month blood-side summary improved: ferritin rose to 61.60 and TSAT recovered to 33.4%, after the 2026-05-12 midpoint draw had shown ferritin 43.28 and TSAT 27.7%. The 2026-05-28 stool repeat then turned FOB negative with stool RBC absent. Together this supports better iron recovery and a cooled occult-blood branch during alcohol/smoking abstinence, without proving the April signal's cause. Oral iron and B12 are tools, not diagnostic shortcuts; celiac/autoimmune-gastritis testing stays trigger-based.

hematology · iron-deficiency · ferritin · transferrin-saturation · gi-bleeding · oral-iron · b12 · homocysteine · celiac · autoimmune-gastritis · malabsorption · vegetarian-diet

Iron, B12 & Malabsorption

Current conclusion

The current state is not iron-deficiency anemia, and not a proven malabsorption syndrome. The useful frame is narrower:
- ferritin previously fell from about 94 to 35 ug/L; late-2025 is now exposure-confounded by likely heavy alcohol/cigarette use, and the next-day 2025-12-23 stool occult blood/RBC test was negative
- April 2026 was different: ferritin was 54.01 with positive stool occult blood + stool RBCs, so that round remains the clearer occult-blood signal
- the 2026-05-12 midpoint draw showed ferritin 43.28 ug/L and TSAT 27.7% under non-fasting post-meal/coffee conditions; the 2026-05-27 end summary then improved to ferritin 61.60 and TSAT 33.4% after zero alcohol/smoking
- hemoglobin has remained normal in the available series
- CRP is normal, so ferritin is not obviously being inflated by acute inflammation
- the stool occult blood / stool RBC branch cooled on 2026-05-28 (FOB negative, stool RBC absent), but recurrence rules still apply because April 2026 was a real stool-positive signal
- B12 is low-normal and recurrently near the lower range: 231 pmol/L on 2026-04-19, with prior values 396, 279, 193, 228, 291 pmol/L
- homocysteine has been upper-normal around 10.6-11.9 μmol/L; folate has historically been adequate
- no current macrocytic anemia signal, but NICE 2024 explicitly says normal hemoglobin/MCV does not rule out B12 deficiency
- old tTG-IgA was negative in 2015; total IgA is high rather than deficient; gastrin was normal in April 2026

Bottom line: repeat trends and source clarification come first. Supplements can run in parallel when justified, but they must not hide whether bleeding or absorption problems persist.

What changes the decision

Result / pattern	Interpretation	Action
Ferritin stable/improving, Hb normal, stool blood clears	Current end-experiment pattern; no active iron-deficiency signal in this snapshot	Monitor / food-first; avoid panic iron loading
Ferritin/TSAT improve after abstinence but stool blood is not yet cleared	Iron recovery improved, bleeding-source question unresolved	Keep alcohol/smoking avoidance; complete repeat stool-blood/direct-exam branch rather than declaring bleeding solved
Ferritin falls toward <45-50 ug/L, TSAT stays <20%, Hb normal	Non-anemic iron depletion becoming more plausible	Conservative oral iron is reasonable while repeating stool/iron trend
Hb starts falling, ferritin drops, stool blood persists	Ongoing loss or mixed process	GI-source escalation matters more than supplement optimization
Visible bleeding, melena, rapid weakness, tachycardia/faintness, Hb drop	Higher-risk bleed/anemia branch	Do not manage with supplements; urgent medical/GI evaluation
Oral iron worsens bloating/constipation significantly	Repletion may confound gut tracking	Stop, reduce, or switch form/frequency
B12 low-normal with brain fog/fatigue/paraesthesia/balance/glossitis/memory symptoms	B12 becomes actionable despite normal CBC	Oral repletion trial plus homocysteine/folate follow-up; clinician review if objective neurologic signs
B12 rises but homocysteine stays high	Look beyond B12	Folate, B6, thyroid, renal function, alcohol relapse, inflammation/gut context; avoid MTHFR rabbit hole unless clinician-directed
B12 does not rise on oral dosing	Dose/product/adherence problem or malabsorption	Consider MMA/active B12 if available and trigger-based malabsorption/autoimmune-gastritis branch
Persistent iron/TSAT drift, chronic non-bloody diarrhea/steatorrhea, weight loss, refractory aphthae, DH-like rash, or persistent unexplained bloating with objective markers	Celiac/malabsorption becomes actionable	tTG-IgA while eating gluten; GI confirmation if positive/high
Poor B12/iron response, rising gastrin, upper-GI features, or gastroscopy already indicated	Autoimmune/atrophic gastritis branch becomes relevant	Intrinsic-factor Ab first for specificity, parietal-cell Ab for sensitivity if available; biopsy distribution matters if scoped

What to do now

If stool follow-up is not already done, repeat the useful trend set rather than chasing isolated serum iron: CBC with indices/RDW, ferritin, serum iron, TIBC or transferrin, TSAT, CRP, and stool-blood/direct-exam follow-up as owned by GI Bleeding / Diverticular / Stool Blood.
Do not make oral iron automatic from the April snapshot. If ferritin/TSAT drift again or symptoms justify repletion, use a conservative regimen:
- ferrous bisglycinate if available/tolerated; otherwise sulfate/fumarate/gluconate are acceptable but often harsher
- 25-36 mg elemental iron every other day to start; consider 45-65 mg only if response is poor and tolerated
- morning empty stomach if tolerated, otherwise with a small non-calcium snack
- optional vitamin C / fruit support
- separate from coffee/tea, calcium, magnesium, zinc, high-fiber supplements, antacids/PPIs if avoidable, and psyllium by about 2 hours or more
- reassess ferritin/TSAT/Hb after 6-8 weeks
Define oral-iron success before starting:
- ferritin rises about 10-30 ug/L, TSAT improves, Hb stable = useful repletion response
- ferritin rises but stool blood persists = tablets are repleting, but source branch remains active
- no ferritin/TSAT response = ongoing loss, poor adherence/timing, malabsorption, wrong dose/form, or inflammation/sequestration
- Hb falls despite iron = escalate
B12: because diet is vegetarian-leaning and B12 is repeatedly low-normal, simple oral support is reasonable without a large panel:
- no clear neurologic symptoms: 1000 mcg cyanocobalamin or methylcobalamin 2-3x/week, or 250-500 mcg/day
- compatible symptoms: 1000 mcg/day for 8-12 weeks, then step down if symptoms/labs improve
- recheck B12 + homocysteine + folate in 8-12 weeks if this becomes an active experiment
- MMA is useful only if accessible or symptoms persist despite adequate oral B12
Malabsorption/celiac: do not automatically add a broad panel. If triggered, ask for the exact test tTG-IgA / anti-TG2 IgA while eating gluten. Add total IgA only if the lab requires same-day pairing; IgA deficiency is already ruled out by elevated total IgA.
Autoimmune gastritis/pernicious branch: do not shotgun now. Trigger only if B12/iron behavior worsens or fails to respond, gastrin rises, upper-GI symptoms appear, or gastroscopy is being done anyway. If scoped, ask for gastric body + antrum/incisura biopsies in separately labelled jars plus H. pylori assessment.

Local availability reminders:

Test	Biomed public status / price	Use
B12	listed, $17.50	repeat only if tracking response
Folate	listed, $16.25	interpret homocysteine
Homocysteine	listed, $25	best local functional proxy if MMA unavailable
MMA / active B12	not listed	do not assume availability
Total IgA	listed, $10	already high; not needed solely to validate tTG
tTG-IgA / anti-TG2 IgA	not listed publicly	ask exact off-menu/send-out wording or another hospital/lab
DGP/EMA/HLA-DQ2/DQ8	not listed publicly	second-line only; HLA-B27 is not a celiac HLA test
Gastrin	listed, $19.50; already normal April 2026	repeat only if suspicion changes
H. pylori stool antigen	listed, $15; prior negative Dec 2025	repeat only with upper-GI/iron-loss trigger or clinician request

What not to do

Do not let iron supplementation make the diagnostic branch disappear. A ferritin bump from tablets does not prove bleeding stopped.
Do not treat black/dark stool on oral iron as proof of bleeding; also do not dismiss visible blood or positive FOB as “just the iron” without clinical/lab context.
Do not delay stool-blood/GI-source workup because oral iron is possible.
Do not run a broad autoimmune/malabsorption panel for bloating alone.
Do not self-diagnose celiac by going gluten-free before testing; negative serology after gluten restriction is unreliable.
Do not substitute HLA-B27 or generic IgA/IgG tests for celiac-specific testing.
Do not use B12 injections by default; reserve clinician/IM-route logic for objective neurologic signs, poor oral response, or strong malabsorption/pernicious concern.
Do not add high-dose B6 casually; chronic excess can cause neuropathy and muddy symptom interpretation.
Do not use IV iron as default. It becomes a clinician discussion if oral iron is not tolerated, ferritin/TSAT fail to respond after 6-8 weeks with good adherence/timing, Hb declines/symptomatic anemia develops, or malabsorption/ongoing loss makes oral repletion unrealistic.

Evidence and owner links

Current owner: Iron, B12 & Malabsorption.
Absorbed detail covered here: oral iron, celiac/autoimmune-gastritis screening, and B12 follow-up.

Evidence anchors retained from the absorbed pages:

Iron deficiency / GI evaluation: AGA IDA guideline PMID: 32810434; BSG IDA guideline PMID: 34497146; AGA Clinical Practice Update on IDA PMID: 38864796; non-anaemic iron deficiency review PMID: 34908363; serum iron variability PMID: 12090432.
Oral iron dosing/tolerability: hepcidin physiology PMID: 26289639; alternate-day absorption PMID: 31413088; alternate-day RCT PMID: 36725875; daily-vs-alternate systematic review PMID: 37979057.
B12 framework: NICE NG239 (2024), Vitamin B12 deficiency in over 16s: diagnosis and management, https://www.nice.org.uk/guidance/ng239.
Adult celiac diagnosis: ESsCD 2025 guideline PMID: 40999951; ACG 2023 guideline update PMID: 36602836.
Autoimmune/atrophic gastritis: AGA atrophic gastritis clinical practice update PMID: 34454714; autoimmune gastritis clinical management review PMID: 34484423; corpus-restricted atrophic gastritis biomarker study PMID: 36428844.

This is the canonical iron/B12/malabsorption owner. Oral iron, B12, celiac, and autoimmune-gastritis decisions should be read here rather than as separate pages.