The diagnosis of beta-thalassemia trait: a review

Favorable Pulse Wave Augmentation Indices and Left Ventricular Diastolic Profile in β-Thalassemia Minor

β-Thalassemia minor (β-Τm) is associated with rheological and biochemical alterations that can affect cardiovascular function. We aimed to evaluate the elastic arterial properties and the pulse wave augmentation indices in a population of patients with β-Τm. Seventy-five individuals with β-Τm (age 55.5 [42.75-65.25], women 48%) and 127 controls (age 57 years [48-63], women 55.1%) underwent comprehensive echocardiographic evaluation and applanation tonometry of the radial and femoral artery. Pulse wave analysis revealed that augmentation pressure, augmentation index (AIx), and heart rate-corrected AIx were significantly lower (median [interquartile range]: 8.75 [4.625-13] vs 11 [6.5-14.5], P = .017; 26.5 [17.5-33.375] vs 30.5 [20.75-37.5], P = .014; and 22.25 [15.125-29.5] vs 27 [20.5-33], P = .008, respectively) in the β-Τm group compared to controls. The left atrial active emptying volume was significantly lower and the isovolumic relaxation time was shorter in the β-Τm group compared to the control group (10.2 [7.4-14.4] vs 12.0 [8.6-15.8], P = .040 and 78 [70-90] vs 90 [70-104], P = .034, respectively). β-Thalassemia minor is associated with favorable pulse wave augmentation indices and left ventricular diastolic function profile in asymptomatic individuals with cardiovascular risk factors.

The rule of four: a systematic approach to diagnosis of common pediatric hematologic and oncologic disorders

The "Rule of Four" facilitates a rapid and focused approach to the diagnosis of the common hematologic and oncologic disorders encountered in general pediatric practice. This system relies on four recurrent but different clinical entities or laboratory tests relevant to the diagnosis of children with anemia, excessive bleeding or clotting, and common malignancies. For each disorder, there is a discussion of a variety of four lab tests or factors pertinent to a differential diagnosis.

Quantification of hemoglobin A2 and identification of hemoglobin variants using a fully automated hemoglobin analyzer

The DIAMAT Analyser System is a fully automated high performance liquid chromatographic (HPLC) instrument originally designed for the quantification of glycated hemoglobin (HbA1c). Buffers were developed for the separation and quantification of hemoglobin A2 on the DIAMAT. Also studied were the retention patterns of various hemoglobin variants on the DIAMAT using the buffers developed for the hemoglobin A2 quantification.

Inadequate utilization of routine electronic RBC counts to identify beta thalassemia carriers

We investigated physician awareness of the diagnosis of beta thalassemia minor as suggested by RBC indices obtained from routine electronic counts; and, the knowledge of the carriers of their genetic trait. Out of 17,000 counts, 324 were compatible with the diagnosis of beta thalassemia minor, but, only 175 (54 per cent) were identified by physicians as possibly thalassemic and in 47 of these (27 per cent) was the diagnosis verified. Twenty-four of 39 interviewed patients in whom the diagnosis of beta thalassemia minor was established knew about their carrier state.

Decreased osmotic fragility in heritable canine myopathy

Osmotic fragility was examined in red blood cells from dogs with a heritable muscle disorder that clinically resembles a muscular dystrophy. Several erythrocyte abnormalities have been reported in patients with certain forms of muscular dystrophy and it is thought that these changes reflect genetically induced alterations in the plasma membrane. It is believed that the examination of erythrocytes may eventually lead to the understanding of membrane involvement in muscle disorders. In this study, the mean osmotic fragility was found to be significantly lower in affected cells than in normal cells. These differences were maintained regardless of changes in incubation temperature (5 degrees, 20 degrees, or 35 degrees C) and pH (6.5, 7.0, 7.5, or 8.0). Quantitative analysis of glycolytic metabolites and adenine nucleotide concentrations revealed little variance between erythrocytes from normal and affected animals. Similarly, the pattern of membrane protein phosphorylation in intact erythrocytes from affected animals did not differ from that observed when erythrocytes from normal animals were examined. Of the red cell indices measured, the erythrocyte count in affected animals was moderately increased, but both the mean corpuscular volume and mean corpuscular hemoglobin content were significantly reduced. From these data it is concluded that the decrease in osmotic fragility cannot be explained by differences in cell metabolism or energy production. However, the decrease in affected cell mean corpuscular volume and mean corpuscular hemoglobin content may be correlated with the decrease in osmotic fragility in a manner similar to that observed in the hemolytic disorder of beta-thalassemia.

The distribution and interaction of haemoglobin variants and the beta thalassaemia gene in Liberia

In a population survey in Liberia, West Africa, 12 major tribes were examined for the prevalence of Hb S, Hb C, and the beta thalassaemia (beta Thal) gene. Hb C is rare; Hb S and beta Thal occur in polymorphic frequencies. The distribution of both genes shows an inverse correlation. The beta Thal trait was diagnosed by quantitation of Hb A2 on DE 52-microchromatography. This method proved to be reliable and useful for mass screening.

The laboratory evaluation of microcytic red blood cells

Microcytic red blood cell states are common clinical problems in both adult and pediatric age groups. The recent widespread availability of electronic blood cell counters for performing routine blood counts has increased the detection of microcytic red blood cells. Physicians must workup both symptomatic and asymptomatic patients with microcytic red blood cells before they can initiate proper therapy and/or counseling. The purpose of this review is threefold: (1) to discuss the causes of microcytic red blood cells in terms of disorders of decreased heme production vs. disorders of decreased globin production, (2) to review the clinical laboratory tests useful in differentiating microcytic red blood cell states, and (3) to present a practical approach for the laboratory workup of microcytic red blood cells.

Thalassemia and pregnancy: results of an antenatal screening program

A thalassemia screening program was implemented at our institution using the finding of a mean corpuscular volume less than 80 fl as the index of abnormality. Further evaluation using hemoglobin (Hb) electrophoresis and serum iron studies was carried out according to the scheme detailed below. A diagnosis of thalassemia was made in 33 women (42 pregnancies). Eight patients had alpha-thalassemia trait, 23 beta-thalassemia trait, and two Hb H disease. Thalassemia trait did not have any adverse effect on pregnancy outcome. In two couples the fetuses were at risk for homozygous disease and in one couple the fetus was at risk for sickle cell beta-thalassemia. The screening program described is an effective and inexpensive means of detecting thalassemia in an antenatal population and is applicable to most every clinic or office setting.

Investigation of microcytic anemia

This article on microcytic anemia is the first of several on laboratory investigation of anemia. Microcytic anemia, characterized by a mean corpuscular volume of less than 80 cu mu, is usually due to iron deficiency or chronic disease but may signify thalassemia minor. Exact identification of the cause is important, since inappropriate iron therapy may be useless or even dangerous.