Nuchprayoon Issarang, Sukthawee Boonruen, Nuchprayoon Thassanee
Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
J Med Assoc Thai. 2003 Jun;86 Suppl 2:S160-9.
Anemia is common among Thai females. Thalassemia and iron deficiency are highly prevalent in the Thai population. A therapeutic trial of iron has been used to differentiate between the two conditions, however, no previous study on its usefulness in a Thai population has been reported. Otherwise healthy persons who had complete blood count (CBC) as routine 'check-up' and found to be anemic (Hb < 12 g/dl) at a preventive medicine clinic were tested for hemoglobin typing, serum ferritin, serum iron, and were given oral iron sulfate (120 mg elemental iron per day for at least 2 months) and a repeat CBC on a follow-up visit. Sixty-six individuals, all females, with pre-treatment hemoglobin (Hb) level of 9.5 +/- 1.7 g/dl (mean +/- SD), had complete data for analysis. Final diagnoses were isolated iron deficiency in 23 (34.8%), iron deficient thalassemia traits in 6 (9.1%) and iron-sufficient thalassemia syndromes in 29 (43.9%) anemic subjects. After a therapeutic trial of iron, Hb rose to 12.8 +/- 1.0 g/dl (n = 16, p = 2 x 10(-8)) among the iron deficient group, but not in thalassemia. The authors have identified that the most useful red cell indices that will discriminate between iron deficiency and thalassemia is a combination of red blood cell counts (RBC) > 4.4 x 10(6)/microl and mean corpuscular volume (MCV) < 69 fl. High RBC (> 4.4 x 10(6)/microl) and very low MCV (< 69 fl) is a sensitive (92.9%) and highly specific (100%) criteria for diagnosis of mild thalassemia diseases (Hemoglobin H (HbH), Hemoglobin H-Constant Spring (HbH-CS), and homozygous Hemoglobin E (HbEE)). Conversely, a low RBC (> 4.4 x 10(6)/microl) and/or low to normal MCV (69-85 fl) is highly sensitive (91.3%) but not specific (60%) for the diagnosis of iron deficiency. The authors conclude that a therapeutic trial of iron is useful as a diagnostic test in anemic females except those with high RBC (> 4.4 x 10(6)/microl) and very low MCV (< 69 fl), a subgroup which most likely has thalassemia and are least likely to benefit from iron treatment.
贫血在泰国女性中很常见。地中海贫血和缺铁在泰国人群中非常普遍。铁剂治疗试验已被用于区分这两种情况，然而，此前尚无关于其在泰国人群中有效性的研究报道。在一家预防医学诊所进行常规“体检”时进行全血细胞计数（CBC）并被发现贫血（血红蛋白<12 g/dl）的健康个体，接受了血红蛋白分型、血清铁蛋白、血清铁检测，并给予口服硫酸亚铁（每天120毫克元素铁，至少服用2个月），并在随访时再次进行全血细胞计数。66名个体，均为女性，治疗前血红蛋白（Hb）水平为9.5±1.7 g/dl（平均值±标准差），有完整数据可供分析。最终诊断为单纯缺铁的有23例（34.8%），缺铁性地中海贫血特征的有6例（9.1%），铁充足的地中海贫血综合征的有29例（43.9%）。在进行铁剂治疗试验后，缺铁组的血红蛋白升至12.8±1.0 g/dl（n = 16，p = 2×10⁻⁸），而地中海贫血组则未升高。作者发现，区分缺铁和地中海贫血最有用的红细胞指标是红细胞计数（RBC）>4.4×10⁶/微升和平均红细胞体积（MCV）<69飞升的组合。高红细胞计数（>4.4×10⁶/微升）和极低平均红细胞体积（<69飞升）是诊断轻度地中海贫血疾病（血红蛋白H（HbH）、血红蛋白H-恒定链（HbH-CS）和纯合血红蛋白E（HbEE））的敏感（92.9%）且高度特异（100%）的标准。相反，低红细胞计数（>4.4×10⁶/微升）和/或低至正常平均红细胞体积（69 - 85飞升）对缺铁诊断具有高度敏感性（91.3%）但不具有特异性（60%）。作者得出结论，铁剂治疗试验作为贫血女性的诊断测试是有用的，但那些红细胞计数高（>4.4×10⁶/微升）且平均红细胞体积极低（<69飞升）的女性除外，这一亚组最可能患有地中海贫血，且最不可能从铁剂治疗中获益。
