Validity of using oral mucosal exfoliative smear as a screening tool of iron overload in β-thalassemia major patients

Introduction
Iron overload is one of the most common life-threatening disorders among thalassemia patients. Iron level is usually monitored using serum ferritin level or chemical assessment of liver biopsy. However, these tests are extremely invasive, especially on repeated use.

Objectives
This study aims to evaluate the validity of using oral mucosal exfoliative smear stained with Perls’ Prussian blue reaction as a tool in qualitative evaluation of iron overload, and assessing the possibility of using cellular expression of Perls’ Prussian blue-stained cells as a tool in quantitative assessment of serum ferritin level in β-thalassemia major patients.

Material and methods
Buccal mucosal scrapings were taken from 69 β-thalassemia major patients (40 males, 29 females), aged 5 to 33 years old (average, 15.4 years), who have undergone blood transfusion for more than 15 times. The scrapings were fixed with methanol (99.8%) and stained with acidified potassium ferrocyanide solution, followed by Gram staining (safranin staining). The scrapings were evaluated using photomicrograph at 40 × 10 magnification.

Results
Among members of the sample, 59 patients (87%) were positive for Perls’ Prussian blue reaction. A moderate positive correlation was found between positivity of Perls’ Prussian blue reaction and serum ferritin level. A moderate positive correlation was also found between expression of iron within oral mucosal exfoliative cells and serum ferritin level.

Conclusions
Oral mucosal exfoliative smear can be used in both qualitative and quantitative evaluation of iron overload.