What is the diagnosis for a patient with leukocytosis (elevated White Blood Cell (WBC) count), neutrophilia (high percentage of neutrophils), iron deficiency anemia (low iron and iron-binding capacity levels), and abnormal complete blood count (CBC) results?

Diagnosis: Bacterial Infection with Concurrent Iron Deficiency Anemia

This patient has a bacterial infection requiring immediate evaluation and treatment, with underlying iron deficiency anemia that needs subsequent management.

Primary Diagnosis: Bacterial Infection

The laboratory findings strongly indicate an active bacterial infection based on multiple high-probability markers:

Key Diagnostic Indicators

• Absolute neutrophil count of 14.3 (thousand/mm³) with 78% neutrophils represents marked neutrophilia that has a likelihood ratio of 7.5 for bacterial infection when neutrophil percentage exceeds 90%, though even at 78% this is highly suggestive 1

• The presence of 2% myelocytes indicates a left shift with immature neutrophils in circulation, which has a likelihood ratio of 4.7 for bacterial infection when band forms reach ≥16% 1, 2

• WBC count of 17 (thousand/mm³) exceeds the threshold of 14,000 cells/mm³, which has a likelihood ratio of 3.7 for detecting bacterial infection 1, 3

• The absolute neutrophil count of 14,300 cells/mm³ far exceeds the critical threshold of 1,500 cells/mm³ for band forms, which carries the highest likelihood ratio (14.5) for documented bacterial infection 1, 2

Immediate Clinical Actions Required

You must immediately assess for clinical signs of focal infection and obtain appropriate cultures before initiating antibiotics 1, 2:

• Check for fever patterns (>100°F/37.8°C, or ≥2 readings >99°F/37.2°C) 1
• Evaluate for respiratory symptoms and obtain chest radiograph 2
• Assess for urinary symptoms (dysuria, gross hematuria, new incontinence) and obtain urinalysis with culture if present 1, 3
• Examine for skin/soft tissue infection, wound drainage, or abdominal symptoms 1
• Obtain blood cultures if bacteremia is suspected based on severity of presentation 2

Secondary Diagnosis: Iron Deficiency Anemia

The hematologic parameters confirm iron deficiency anemia:

Iron Deficiency Markers

• Serum iron of 36 mcg/dL with TIBC of 253 mcg/dL indicates iron deficiency with a transferrin saturation of approximately 14% (well below the normal 20-50%) 4

• MCV of 107.6 fL is actually macrocytic, not the expected microcytosis of iron deficiency, which suggests a mixed picture or concurrent process 4, 5

• MCH of 35.8 pg is elevated, again suggesting macrocytosis rather than typical iron deficiency 5

Important Caveat About the Anemia

The macrocytic indices (elevated MCV and MCH) are atypical for pure iron deficiency anemia and warrant further investigation 5:

• Iron deficiency typically causes microcytic anemia (low MCV), not macrocytic 4
• Neutrophil hypersegmentation can occur in iron deficiency anemia (present in 62% of cases), but macrocytosis more commonly suggests B12 or folate deficiency 5
• Check vitamin B12 and folate levels once the acute infection is managed 5

Reactive Leukocytosis from Iron Deficiency

• Severe iron deficiency can cause reactive leukocytosis and thrombocytosis, though this is exceptional 6
• However, the presence of left shift with myelocytes strongly favors bacterial infection as the primary cause of leukocytosis rather than reactive changes from anemia alone 1, 6

Clinical Pitfalls to Avoid

• Do not attribute the leukocytosis solely to iron deficiency - the left shift and neutrophilia pattern are much more consistent with bacterial infection 1, 6

• Do not delay antibiotic therapy if clinical signs of infection are present, as the laboratory findings strongly support bacterial infection requiring prompt treatment 1, 2

• Do not rely on WBC count alone - the absolute neutrophil count, neutrophil percentage, and presence of immature forms (myelocytes) provide much stronger diagnostic information than total WBC 1, 7

• Do not ignore the atypical macrocytic picture - investigate for concurrent B12/folate deficiency after addressing the acute infection 5

Management Priority Algorithm

1. Immediate (within hours): Identify source of bacterial infection through targeted history, physical exam, and appropriate cultures 1, 2
2. Urgent (within 24 hours): Initiate appropriate antibiotic therapy based on suspected source 2
3. Short-term (days): Monitor response to antibiotics and repeat CBC to assess resolution of leukocytosis 3
4. Follow-up (weeks): Investigate mixed anemia picture with B12/folate levels and initiate iron supplementation 5, 6