Synthetic data only. Never enter patient information; nothing is sent or stored. For clinicians. Not FDA cleared.For licensed clinicians. Educational demonstration on synthetic data. Never enter real patient identifiers or protected health information: everything runs in your browser and nothing is sent or stored. Clinical decision support only; not FDA cleared; physician review is required.
CPE-004 · version 1.0.0
Iron Deficiency Pattern Engine: ferritin, inflammation and the anemia behind it
Iron status from ferritin and transferrin saturation, read correctly when inflammation, heart failure or kidney disease changes the rules.
A normal CBC does not exclude iron deficiency, and a normal ferritin does not exclude it either when inflammation is present. The Iron Deficiency Pattern Engine reads ferritin against the right cutoff for the patient in front of it and then asks what the iron indices, MCV, RDW and Mentzer index say about the type of anemia.
It also keeps the safety questions in front: iron-deficiency anemia in a man or a postmenopausal woman needs a gastrointestinal source considered, severe anemia is escalated, and the engine never names an iron product, dose or duration.
Playground
Load a synthetic case or type your own values. The result recomputes as you type, and every rule links to its page.
Stage of iron deficiency
✓ 1 · Stores depleted
Low ferritin, normal CBC
✓ 2 · Iron-deficient erythropoiesis
Low TSAT or reticulocyte Hb, Hb still normal
● 3 · Anemia
Hemoglobin below the WHO threshold
Against typical reference intervals
Iron studiesDrag or type
- <15 depleted
- 15–29 low
- 30–44 borderline
- 45–299
- 300–999 high
- >1000 very high
Calculated from iron ÷ TIBC when both are entered.
Above 5 mg/L the engine reads ferritin as inflammation-affected.
CBC
- <7 severe
- 7–11.9 anemia range
- 12–12.9 (men <13)
- ≥13
Patient
Symptoms and findings
Conditions and risk groups
Work-up and treatment context
What it does
- Applies the WHO ferritin cutoffs (below 15, and below 70 with inflammation) alongside the 30 ng/mL and AGA 45 ng/mL levels in common use.
- Stages iron deficiency: stores depleted, iron-deficient erythropoiesis, anemia.
- Separates iron-deficiency anemia from anemia of inflammation, thalassemia trait and iron overload using ferritin, saturation, RDW and the Mentzer index.
- Applies the heart-failure iron-deficiency definition and prompts iron studies in CKD with anemia.
- Raises gastrointestinal-evaluation, severe-anemia, overt-bleeding and refractory-to-oral-iron alerts.
What it never does
- Name an iron product, dose, route or duration.
- Attribute fatigue, hair loss or restless legs to iron on its own.
- Show a confidence score or claim a sensitivity for a symptom.
- Diagnose hemochromatosis from ferritin and saturation.
Safety gates
These gates run before the pattern is shown, and urgent findings are displayed first.
- Hemoglobin below 7 g/dL, or below 8 with chest pain, dyspnea at rest or syncope, raises an urgent alert.
- Melena, hematochezia or hematemesis with anemia or iron deficiency raises an urgent alert.
- Iron-deficiency anemia in a man or postmenopausal woman raises a gastrointestinal-evaluation alert.
- Ferritin above 1,000 ng/mL or an iron-overload pattern raises a priority review.
Inputs
- Ferritin, serum iron, TIBC or transferrin saturation
- Hemoglobin, MCV, MCH, RDW, RBC count, reticulocyte hemoglobin
- hs-CRP and inflammation status
- Sex, age, menopause, pregnancy
- Heart failure, CKD, bleeding, diet, donor and surgical history
Scope
In scope
- Adults aged 18 and over
- Pregnant adults (pregnancy hemoglobin threshold)
Routed out
- Patients under 18
The full rule catalog
29 active rules and 2 sandbox or context entries. Each has its own page with conditions, outputs and evidence. 31 of 31 active rules are exercised by at least one synthetic case.
Scope and validity
Iron status
Anemia
Safety
Context triggers
ID-HF-01
Heart failure without iron studies
ID-CKD-01
Chronic kidney disease with anemia
ID-RLS-01
Restless legs and iron status
ID-HAIR-01
Diffuse hair loss and ferritin
ID-PICA-01
Pica or pagophagia
ID-RISK-01
High-risk group without recent iron studies
ID-IV-01
Intravenous iron under consideration with active infection
Calculations
Missing data
Synthetic cases
Every case is synthetic. Open one to see the inputs, the full result and the rule trace; then change the values.
IRON-FX-01
Classic iron-deficiency anemia in a premenopausal woman
A 34-year-old with heavy periods, Hb 9.8, MCV 72 and a ferritin of 6.
IRON-FX-02
Normal CBC, low ferritin, fatigue and hair loss
A 29-year-old with a normal CBC and a ferritin of 18.
IRON-FX-03
Iron-deficiency anemia in a man
A 61-year-old man with Hb 10.9, MCV 76 and a ferritin of 9.
IRON-FX-04
Iron-deficiency anemia after menopause
A 67-year-old woman, postmenopausal, Hb 10.6, ferritin 11.
IRON-FX-05
Rheumatoid arthritis: ferritin 85, TSAT 12
Hb 10.4 with a ferritin that looks normal and a CRP of 18.
IRON-FX-06
Inflammation with ferritin 48 and TSAT 9
Ferritin looks near normal but sits under the WHO inflammation cutoff of 70.
IRON-FX-07
Microcytic anemia with preserved iron indices
MCV 62, RBC 5.6, ferritin 95 and TSAT 28.
IRON-FX-08
Heart failure with ferritin 82
A 70-year-old man with heart failure and a normal hemoglobin.
IRON-FX-09
Heart failure with ferritin 180 and TSAT 14
Ferritin 100–299 with low saturation meets the heart-failure definition.
IRON-FX-10
Heart failure and no iron studies
A patient with heart failure and no ferritin or saturation on file.
IRON-FX-11
Anemia in chronic kidney disease
Hb 10.2, ferritin 140 and TSAT 17 in CKD.
IRON-FX-12
Restless legs with ferritin 52
Ferritin is above the usual cutoffs but under the restless-legs threshold.
IRON-FX-13
Severe anemia
Hemoglobin 6.4 g/dL with a ferritin of 4.
IRON-FX-14
Anemia with overt gastrointestinal bleeding
Black stools and Hb 8.9.
IRON-FX-15
Ferritin 780 with transferrin saturation 71%
A 45-year-old man with high saturation and high ferritin.
IRON-FX-16
Ferritin 1,450 during inflammation
A very high ferritin with a CRP of 60.
IRON-FX-17
Iron-deficiency anemia in pregnancy
A pregnant woman with Hb 10.2 and a ferritin of 11.
IRON-FX-18
Four months of oral iron without response
Adherent for four months, ferritin still 12.
IRON-FX-19
Vegetarian endurance athlete, no ferritin on file
A 22-year-old with a normal CBC and no iron studies.
IRON-FX-20
IV iron considered during a urinary infection
Ferritin 14 and an active infection.
IRON-FX-21
A child is outside the adult pathway
Nine years old.
IRON-FX-22
Ice craving with a ferritin of 22
Pagophagia and a low ferritin.
IRON-FX-23
Borderline ferritin with fatigue
Ferritin 38, Hb 12.8 and fatigue.
IRON-FX-24
No iron-deficiency criterion
A 40-year-old man with ferritin 120 and Hb 15.
IRON-FX-25
Iron-deficient erythropoiesis before anemia
Hb 12.4 but TSAT 11% and reticulocyte Hb 25 pg.
Evidence
Guidelines and references the rules cite. Each rule page lists the ones that support it.
EV-WHO-FERR-2020World Health Organization. WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. Geneva: WHO; 2020.
Supports: Ferritin below 15 µg/L indicates iron deficiency in healthy adults A higher cutoff (<70 µg/L) applies in the presence of infection or inflammation
EV-WHO-HB-2011World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Geneva: WHO; 2011.
Supports: Anemia thresholds: hemoglobin <13.0 g/dL (men), <12.0 g/dL (non-pregnant women), <11.0 g/dL (pregnancy)
EV-AGA-2020Ko CW, Siddique SM, Patel A, et al. AGA Clinical Practice Guidelines on the Gastrointestinal Evaluation of Iron Deficiency Anemia. Gastroenterology. 2020;159(3):1085-1094.
Supports: A ferritin cutoff of 45 ng/mL is suggested to diagnose iron deficiency Bidirectional endoscopy is suggested for asymptomatic men and postmenopausal women with iron-deficiency anemia Celiac serology and H. pylori testing have a role in evaluation
EV-CAMASCHELLA-2015Camaschella C. Iron-deficiency anemia. N Engl J Med. 2015;372(19):1832-1843.
Supports: Stages of iron deficiency, causes and differential diagnosis of microcytic anemia
EV-LOPEZ-2016Lopez A, Cacoub P, Macdougall IC, Peyrin-Biroulet L. Iron deficiency anaemia. Lancet. 2016;387(10021):907-916.
Supports: Risk groups, causes and evaluation of iron deficiency anemia
EV-AHA-HF-2022Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure. Circulation. 2022;145(18):e895-e1032.
Supports: Iron deficiency in heart failure: ferritin <100 ng/mL, or 100–299 ng/mL with transferrin saturation <20%
EV-KDIGO-ANEMIA-2012KDIGO Anemia Work Group. KDIGO Clinical Practice Guideline for Anemia in Chronic Kidney Disease. Kidney Int Suppl. 2012;2(4):279-335.
Supports: Assess iron status before ESA therapy Iron trial in anemic CKD with transferrin saturation ≤30% and ferritin ≤500 ng/mL
EV-IRLSSG-2018Allen RP, Picchietti DL, Auerbach M, et al. Evidence-based and consensus clinical practice guidelines for the iron treatment of restless legs syndrome/Willis-Ekbom disease in adults and children. Sleep Med. 2018;41:27-44.
Supports: Consider iron when ferritin is ≤75 µg/L or transferrin saturation is <20%
EV-ACG-CELIAC-2023Rubio-Tapia A, Hill ID, Semrad C, et al. American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease. Am J Gastroenterol. 2023;118(1):59-76.
Supports: Celiac serology is appropriate in unexplained iron-deficiency anemia
EV-EASL-HFE-2022European Association for the Study of the Liver. EASL Clinical Practice Guidelines on haemochromatosis. J Hepatol. 2022;77(2):479-502.
Supports: Transferrin saturation >45% as the first-line screen Ferritin above 200 µg/L (women) or 300 µg/L (men) with raised saturation prompts HFE testing
EV-ACOG-ANEMIA-2021American College of Obstetricians and Gynecologists. Anemia in Pregnancy. ACOG Practice Bulletin No. 233. Obstet Gynecol. 2021;138(2):e55-e64.
Supports: Pregnancy anemia thresholds; ferritin below 30 ng/mL suggests iron deficiency in pregnancy
EV-TROST-2006Trost LB, Bergfeld WF, Calogeras E. The diagnosis and treatment of iron deficiency and its potential relationship to hair loss. J Am Acad Dermatol. 2006;54(5):824-844.
Supports: Iron deficiency may contribute to diffuse hair loss; ferritin is part of the evaluation
EV-MENTZER-1973Mentzer WC Jr. Differentiation of iron deficiency from thalassaemia trait. Lancet. 1973;1(7808):882.
Supports: MCV ÷ RBC count below 13 favors thalassemia trait; above 13 favors iron deficiency
EV-IV-LABELU.S. Food and Drug Administration. Prescribing information for the specific intravenous iron product (verify current labeling).
Supports: Product-specific warnings, including hypersensitivity and infection precautions
Frequently asked questions
Which ferritin cutoff does the engine use?
It applies several, and shows which one it used. Below 15 ng/mL meets the WHO criterion. Between 15 and 29 is flagged as low, the level many guidelines use. Between 30 and 44 is borderline (the AGA 2020 cutoff is 45), considered only with anemia or symptoms. With inflammation the WHO cutoff rises to 70 ng/mL.
Why does inflammation change the interpretation?
Ferritin is an acute-phase reactant, so inflammation can lift it into the normal range while iron stores are empty. When inflammation is documented or hs-CRP is above 5 mg/L, the engine uses the higher WHO cutoff and weighs transferrin saturation.
Does it recommend an iron product or a dose?
No. It reports the pattern and what to check next. Choosing a product, route or dose is a physician decision, and the output states that.
When does it ask for a gastrointestinal evaluation?
When the pattern is iron-deficiency anemia in a man or a postmenopausal woman, in line with the AGA 2020 guideline. In premenopausal women it asks for menstrual blood loss to be quantified and keeps a gastrointestinal source open.
How does the engine tell iron deficiency from thalassemia trait?
In microcytic anemia it compares ferritin, transferrin saturation, RDW and the Mentzer index (MCV ÷ RBC count). A Mentzer index below 13 with preserved iron indices favors thalassemia trait and suggests hemoglobin electrophoresis; it never diagnoses it.
Specification status: Executable specification v1.0.0, authored by Biod from the narrative CPE-004 specification and current guidelines. Reviewed by Dr. Vinicius Amaral, D.O. Not for clinical production use.
Clinical review: Dr. Vinicius Amaral, D.O., Medical reviewer, 2026-10-03.
Keep going
CPE-001
Thyroid Function Pattern Engine
Functional state from TSH and FT4, kept separate from etiology. Central disease and decompensation never hide.
CPE-003
Chronic Kidney Disease Pattern Engine
No CKD label from a single result. Safety gates run first, then chronicity, then CGA.
CPE-010
PCOS Pattern Engine
Two of three criteria in adults, irregular cycles plus hyperandrogenism in adolescents, and PCOS only after other causes are excluded.
CPE-009
Vitamin B12 and Folate Pattern Engine
Serum B12, MMA and homocysteine read together, folic acid never ahead of B12, and neurologic involvement kept in front.
Resources
Micronutrient patterns and cognitive dysfunction
Game
Pattern challenge
Guess what the engine will report.
Try Biod in your practice
The Clinical Intelligence Layer — transforming fragmented clinical information into structured intelligence for clinician review and action.