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CPE-009 · synthetic case B12-FX-03
Borderline B12 and no confirmatory test
B12 250.
Purpose: B12 250.
Inputs the engine received
Laboratory
- Serum vitamin B12
- 250 pg/mL
Patient
- Age
- 48 years
- Sex
- Male
What the engine reports
Detected clinical pattern
Borderline B12 — Confirmatory Test Needed
A serum B12 between 200 and 300 pg/mL does not settle the question. Methylmalonic acid and homocysteine can.
- B12 level: B12 250 pg/mL · borderline
Recommended next steps
For physician consideration. Urgent review always comes first.
- 1Consider methylmalonic acid (with homocysteine) when deficiency is suspected.
Missing information
- Methylmalonic acid (and homocysteine) to settle a borderline B12.
Evidence and rule trace · 1 rules
B12-03Borderline B12, confirmatory test not done
Inputs: serum B12 250 pg/mL (200–300) · MMA and homocysteine not entered
Borderline: a serum B12 in this range does not settle the question.
Evidence
- EV-BSH-2014 · Devalia V, Hamilton MS, Molloy AM; British Committee for Standards in Haematology. Guidelines for the diagnosis and treatment of cobalamin and folate disorders. Br J Haematol. 2014;166(4):496-513.
- EV-GREEN-2017 · Green R, Allen LH, Bjørke-Monsen AL, et al. Vitamin B12 deficiency. Nat Rev Dis Primers. 2017;3:17040.
Physician adjudication required. Clinical decision support for physician review. This output identifies laboratory patterns and safety considerations. It does not diagnose, find the cause, or select a vitamin product, dose or route. Physician adjudication is required.
Change the values
The same engine, starting from this case. Change any value and watch the pattern and the rule trace react.
Serum B12 level
✓ Below 200 pg/mL
Deficiency pattern
● 200 to 300 pg/mL
Borderline: MMA and homocysteine settle it
○ Above 300 pg/mL
Deficiency unlikely, not excluded
Laboratory
- <200
- 200–300
- >300
Patient
Neurologic features
Drugs, diet and risk groups
More b12 cases
B12-FX-01
B12 of 150 pg/mL with macrocytic anemia
A 67-year-old with MCV 108.
B12-FX-02
Borderline B12 with raised MMA
B12 260 and MMA 0.52.
B12-FX-04
Macrocytic anemia, folic acid ordered, no B12
A safety situation.
B12-FX-05
Neuropathy, B12 220 and metformin for five years
Neurologic features with a borderline level.
B12-FX-06
Posterior-column signs and spasticity
A pattern compatible with subacute combined degeneration.
B12-FX-07
Macrocytosis in a patient with alcohol use disorder
MCV 104, B12 not measured.
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