Hemoglobin (Hgb)
CBCNormal range
M 14–18 g/dL · F 12–16 g/dL
SI: M 140–180 g/L · F 120–160 g/L
Critical low: < 7 g/dL · Critical high: > 20 g/dL
☎ When to call
Acute drop of ≥ 2 g/dL, Hgb < 7 (or below the ordered threshold), or any drop with hypotension/tachycardia — call the provider; anticipate type & screen and transfusion orders.
What you do
- Assess the patient, not the number: fatigue, pallor, tachycardia, dyspnea
- Look for a bleeding source — check stool, urine, drains, surgical sites
- Know your transfusion threshold order (often < 7, or < 8 cardiac)
Causes of HIGH hemoglobin
Causes of LOW hemoglobin
Source: Pagana, Mosby's Manual of Diagnostic and Laboratory Tests, 7th ed.Reference only — verify against your facility's policy.
