Low hemoglobin density potential marker of iron availability.

Background: Low hemoglobin density (LHD%) is a new parameter provided by Beckman-Coulter derived from the mean cell hemoglobin concentration, using the mathematical sigmoid transformation LHD% = 100×√(1-(1/(1 + e(1.8(30-MCHC)))). This study investigated the reliability of LHD% for the assessment of iron status in the presence of inflammation.

Methods: Healthy subjects (n = 90) and patients with iron deficiency (IDA, n = 110), chronic kidney disease (CKD, n = 65) and anemia of chronic disease (ACD, n = 85; 24 were iron deficient and 61 were iron sufficient) were analyzed on a LH 780 analyzer (Beckman Coulter Inc., Miami, FL, USA). Independent samples U test and receiver operating characteristic (ROC) curve analysis were applied. To determine the concordance between LHD% and soluble transferrin receptor (sTrR) Cohen's κ index was calculated.

Results: LHD % values showed no statistical difference in patients with IDA and patients with ACD accompanied with IDA (P = 0.6427); LHD% values in these patients were significantly different (P < 0.0001) compared with the iron-sufficient patients with ACD. ROC analysis for LHD% in the detection of iron deficiency showed the following: area under curve 0.903; cut off 5.5%, sensitivity 88.6%, specificity 76.9%; κ index, 0.65.

Conclusions: LHD% is a reliable parameter for the detection of iron deficiency in patients with anemia in the presence of inflammation.