Peripheral Blood Report and Differential Diagnosis

The patient's CBC results show a mild anemia with a hemoglobin level of 10.9 g/dL, a slightly low RBC count, and a normal WBC count with a relatively normal differential. The platelet count is within the normal range. The MCV (Mean Corpuscular Volume) is at the lower end of the normal range, indicating normocytic anemia, but the RDW (Red Cell Distribution Width) is elevated, suggesting a variation in red blood cell size, which can be seen in iron deficiency anemia or mixed anemia.

For a more detailed analysis and to narrow down the differential diagnosis, additional information such as the patient's clinical presentation (e.g., symptoms, medical history), physical examination findings, and possibly other laboratory results (e.g., iron studies, reticulocyte count, vitamin B12 and folate levels) would be beneficial.

Differential Diagnosis

• Single Most Likely Diagnosis
  • Iron Deficiency Anemia: The patient's mild anemia, low MCH (Mean Corpuscular Hemoglobin) and MCHC (Mean Corpuscular Hemoglobin Concentration) at the lower end of normal, and elevated RDW are consistent with iron deficiency anemia, especially in a young female where menstrual blood loss is a common cause.
• Other Likely Diagnoses
  • Anemia of Chronic Disease: This could be considered if the patient has a chronic condition (e.g., autoimmune disease, chronic infection). The normocytic anemia and elevated RDW might support this, but more specific markers (e.g., ferritin, transferrin saturation) would be needed.
  • Mixed Anemia: Given the patient's normocytic anemia with an elevated RDW, a mixed picture (e.g., iron deficiency plus another cause like vitamin deficiency) could be possible.
• Do Not Miss Diagnoses
  • Sickle Cell Disease or Other Hemoglobinopathies: Although less likely given the MCV is at the lower end of normal, these conditions can sometimes present with normocytic anemia, especially if there's a recent hemolytic episode. An elevated RDW can also be seen.
  • Leukemia or Lymphoma: Although the WBC count is normal, and the differential is relatively normal, any abnormality in the blood count warrants consideration of these diagnoses, especially if there are other clinical signs or symptoms.
• Rare Diagnoses
  • Thalassemia: Typically presents with microcytic anemia, but some forms can have a normocytic or slightly microcytic picture. The MCV and RDW might not fully support this, but it's a consideration in certain ethnic backgrounds or with specific clinical findings.
  • Myelodysplastic Syndromes (MDS): These are a group of disorders caused by poorly formed or dysfunctional blood cells, which could potentially present with a normocytic anemia and elevated RDW, though typically seen in older populations.

Conclusion

A definitive diagnosis would require additional clinical information, physical examination findings, and possibly further laboratory testing, including iron studies, reticulocyte count, and examination of the peripheral blood smear. The patient's age, sex, and symptoms (if any) would guide the selection of these tests.