Is a Ferritin of 29 ng/mL Low?
Yes, a ferritin level of 29 ng/mL is considered low and indicates depleted iron stores that warrant clinical attention and likely further evaluation.
Diagnostic Thresholds Based on Current Guidelines
The interpretation of your ferritin level depends critically on clinical context, but 29 ng/mL falls below multiple evidence-based thresholds:
Standard Diagnostic Cutoffs
- Ferritin <30 ng/mL generally indicates low body iron stores 1
- Ferritin <45 ng/mL provides optimal sensitivity (85%) and specificity (92%) for diagnosing iron deficiency, maximizing detection while minimizing false positives 2
- The most recent ASH guidelines (2026) recommend ferritin ≤20 ng/mL as a threshold for iron deficiency in specific populations 3
Your level of 29 ng/mL sits in a diagnostic gray zone - above the most stringent cutoff of 20 ng/mL but below the 30-45 ng/mL range that most guidelines consider indicative of low iron stores.
Clinical Significance by Population
For Men and Postmenopausal Women
At 29 ng/mL, you should be evaluated for:
- Gastrointestinal blood loss - bidirectional endoscopy is recommended if you have anemia 2, 1
- GI malignancy risk - low ferritin in older men is associated with increased GI cancer risk (HR 1.27) 4
- Increased bleeding risk - men with low ferritin have doubled risk of GI bleeding (HR 2.03) 4
For Premenopausal Women
GI investigation is generally not warranted unless you have:
- GI symptoms
- Family history of GI disease
- No obvious menstrual or pregnancy-related blood loss 1
Critical Caveats
Inflammation Masks True Iron Deficiency
Ferritin is an acute phase reactant - if you have any inflammatory condition (infection, chronic disease, malignancy), your ferritin may appear falsely "normal" despite true iron deficiency:
- In inflammatory states, ferritin <45 ng/mL should raise suspicion for iron deficiency 2, 1
- Research shows ferritin levels >50 ng/mL can still represent iron deficiency in the presence of inflammation 5
- Ferritin >150 ng/mL essentially rules out absolute iron deficiency, even with inflammation 1
Additional Testing May Be Needed
If inflammation is suspected, consider:
- Transferrin saturation (TSAT) - guides whether iron deficiency is present 6
- C-reactive protein - identifies concurrent inflammation 2
- Soluble transferrin receptor/log ferritin ratio - superior discrimination in chronic disease 1, 5
Actionable Algorithm
Step 1: Check if you have anemia (Hb <110 g/L in men, <100 g/L in non-menstruating women)
Step 2: If anemic with ferritin 29 ng/mL:
- Men/postmenopausal women → bidirectional endoscopy 2
- Premenopausal women → treat iron deficiency; investigate only if GI symptoms present 1
Step 3: If NOT anemic (non-anemic iron deficiency):
- Men/postmenopausal women → low threshold for GI investigation 1
- Premenopausal women → iron supplementation, no routine investigation 1
Step 4: If inflammatory markers elevated or chronic disease present:
- Consider additional iron studies (TSAT, sTfR)
- May need higher ferritin threshold (up to 45 ng/mL) for diagnosis 2, 1
Long-Term Health Implications
Beyond anemia, low ferritin at 29 ng/mL carries prognostic significance:
- Cardiovascular risk: Low ferritin (<30 ng/mL) independently predicts heart failure development (HR 2.24), even without anemia 7
- Quality of life: Iron deficiency causes fatigue, reduced exercise capacity, and cognitive impairment before anemia develops
Bottom Line
At 29 ng/mL, your ferritin indicates depleted iron stores requiring evaluation for underlying causes, particularly GI blood loss if you are male or postmenopausal. The specific workup intensity depends on whether you have anemia, your sex/menopausal status, presence of GI symptoms, and any inflammatory conditions. This level should not be dismissed as "borderline" - it represents true iron depletion in most clinical contexts 2, 1.