What your micronutrient test results actually mean
Lab reports give you numbers and a range. They don’t tell you what the numbers mean together. This site explains iron, ferritin, vitamin D and B12 results the way clinicians read them — as patterns — and tells you plainly when a result is worth taking back to your doctor.
Start with iron
Iron deficiency is one of the most common nutrient deficiencies in the world, and the iron panel is the result people find hardest to read: five numbers that only make sense side by side. Find your pattern below.
| Pattern | Ferritin | Serum iron | TIBC | Saturation | What it usually means |
|---|---|---|---|---|---|
| Iron deficiency | ↓ low | ↓ | ↑ | ↓ <20% | Iron stores are used up. The body makes more transferrin to find iron, so TIBC rises. |
| Early iron depletion | ↓ low–borderline | ~ | ~↑ | ~ | Stores are falling but blood iron is still holding up. Hemoglobin is often normal. |
| Inflammation or chronic illness | ~↑ | ↓ | ↓ | ↓ | Iron is present but locked away. Low TIBC is what separates this from deficiency. |
| Deficiency plus inflammation | ~ can look normal | ↓ | ~↓ | ↓ <20% | Inflammation props ferritin up and hides a real shortage. Usually needs CRP to read. |
| Possible iron overload | ↑ | ↑ | ↓ | ↑ >45% | High saturation — not high ferritin alone — is what prompts testing for hemochromatosis. |
| High ferritin, normal saturation | ↑ | ~ | ~ | ~ | The most common high-ferritin result. Usually inflammation, liver, alcohol or metabolic — not overload. |
| Unremarkable | ~ | ~ | ~ | ~ | Iron status looks adequate. If symptoms continue, iron is unlikely to be the cause. |
↑ above range · ↓ below range · ~ within range. Patterns are a starting point for a conversation with your clinician, not a diagnosis.
Guides
- What is a good ferritin level?Why “in range” and “enough” are different numbers.
- High TIBCUsually means iron is low, not high.
- Low TIBCUsually inflammation — not deficiency.
- UIBCThe empty half of your iron-carrying capacity.
- What testing costsAnd why the narrow test is usually the right one.
- Labcorp vs. QuestWhy two labs print two different ranges.