FerritinStores
22µg/L
In range, but under the 30 µg/L threshold. Stores are likely low.
One blood draw. Four numbers.
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. It measures stores, transit and carriers from the same sample, and each number only makes sense next to the others.
FERRITIN 22 µg/L 15–150 SERUM IRON 48 µg/dL 50–170 L TIBC 412 µg/dL 250–450 SATURATION 12 % 15–55 L
Serum ironIn transit
48µg/dL
Just below range. It swings with meals and time of day, so it never decides alone.
TIBCCarriers
412µg/dL
High end of range. The body is making more transferrin to find iron.
Saturation% filled
12%
Under 20%. Few carriers are loaded, which fits low supply.
Reports print ranges. Clinicians read thresholds.
A reference range describes what is common in the population a lab tested. A threshold marks where deficiency becomes likely. A result can pass one and miss the other.
What the report saysExample
1FERRITIN, SERUM
2 result 22 ng/mL
3 reference 15–150
−4 flag none
5 ng/mL = µg/L, same number
How it is commonly readWHO 2020 · AGA 2020
1FERRITIN, SERUM
2 result 22 µg/L
3 threshold <30, deficiency likely
+4 read below threshold
5 check CRP: inflammation raises ferritin
Seven patterns cover most results.
We read a panel the way a clinician scans it: range, then threshold, then the pattern the numbers make together.
Reading the exampleAdults, not pregnant
✓ ferritin 22 µg/L · below 30✓ saturation 12% · below 20%✓ TIBC 412 µg/dL · high end– CRP not on report● Closest pattern · iron deficiency
Take to your appointment3 questions
- Is a ferritin of 22 low enough to explain my symptoms?
- Should we check CRP and a full blood count before deciding?
- What could be causing low iron in my case?
Read range→Check threshold→Match pattern
Find your pattern
All 7 patterns ↓Iron deficiency
Stores used up. TIBC rises as the body looks for iron.
Inflammation
Iron is present but locked away. Low TIBC tells it apart.
Possible overload
Saturation above 45% is what prompts further testing.
High ferritin alone
The most common high result. Usually not overload.
| 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 TIBC
Usually means iron is low, not high.
Low TIBC
Usually inflammation, not deficiency.
UIBC
The empty half of your iron-carrying capacity.
What testing costs
And why the narrow test is usually the right one.
Labcorp vs. Quest
Why two labs print two different ranges.
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