A clinical approach to "idiopathic" normocytic-normochromic anemia.

OBJECTIVES: Normocytic-normochromic anemia is frequently found in patients with chronic disorders. The pathogenesis, epidemiological and clinical characteristics of normocytic normochromic anemia of unknown cause are not well established. We evaluated the role of bone marrow examination and the clinical course of patients with "idiopathic" normocytic-normochromic anemia.

DESIGN: Patients with normocytic-normochromic anemia underwent a noninvasive evaluation according to a predetermined protocol. Bone marrow aspiration and biopsy were performed in those patients in whom no explanation for the anemia was found. They were later followed at 3 to 6 month intervals.

RESULTS: Thirty-one patients (23 females and 8 males) with "idiopathic" normocytic-normochromic anemia (mean hemoglobin concentration was 10.0 + 0.6 g/dL) were detected. No patient had symptoms related to the anemia. Twenty-nine bone marrow aspirations and 21 biopsies were performed. Iron deficiency and mild myelofibrosis were found in one patient each. The rest of the bone marrow examinations were normal. During 15.5 +/- 10.3 months of follow-up, the hemoglobin level rose marginally to 10.9 + 1.0 g/dL (P < .0002). No changes in clinical or laboratory variables that could be ascribed to anemia were detected.

CONCLUSION: Normocytic-normochromic anemia of unknown cause is encountered infrequently in clinical practice and is found mainly in older patients. The evaluation should be noninvasive to exclude correctable causes of the anemia. Bone marrow examination is only rarely contributive in this setting. The prognosis of these patients is excellent.