ABSTRACT
ß-Thalassemia (ß-thal) and iron deficiency cause most microcytic anemias. Red cell indices and formulas have been established as simple, fast, and inexpensive in discrimination between these two hematological disorders in school children. However, whether these formulas could be applied to diagnose ß-thal trait and iron deficiency in adult Thai subjects is unclear. The aim of this study was to examine the diagnostic accuracy of five red cell indices [red blood cell (RBC) counts, mean corpuscular volume (MCV), mean corpuscular hemoglobin (Hb) (MCH), mean corpuscular Hb concentration (MCHC), and red cell distribution width (RDW)] and nine formulas (RDW/RBC, RDW Index, Sirdah, Green and King, Mentzer, England and Fraser, Ehsani, Srivastava and Shine and Lal). Their sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV), efficiency, and Youden's Index were analyzed in 102 ß-thal trait and 64 iron deficiency adult Thai subjects. The RDW/RBC formula proved to be the most reliable index as they had 100.0% specificity and PPV and the highest efficiency (94.58%) and Youden's Index (91.18%), as well as high sensitivity (91.18%) and NPV (87.67%). Therefore, this formula could be used in initial discrimination of ß-thal trait from iron deficiency in adult Thai subjects.
Subject(s)
Anemia, Iron-Deficiency/blood , Anemia, Iron-Deficiency/diagnosis , Erythrocyte Indices , beta-Thalassemia/blood , beta-Thalassemia/diagnosis , Adult , Aged , Aged, 80 and over , Biomarkers/blood , Diagnosis, Differential , Female , Humans , Iron/blood , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Thailand , Young AdultABSTRACT
BACKGROUND: Prevention and control of thalassemia requires simple, rapid, and accurate screening tests for carrier couples who are at risk of conceiving fetuses with severe thalassemia. METHODS: Single-tube multiplex real-time PCR with SYBR Green1 and high-resolution melting (HRM) analysis were used for the identification of α-thalassemia-1 Southeast Asian (SEA) and Thai type deletions and ß-thalassemia 3.5-kb gene deletion. The results were compared with those obtained using conventional gap-PCR. DNA samples were derived from 28 normal individuals, 11 individuals with α-thalassemia-1 SEA type deletion, 2 with α-thalassemia-1 Thai type deletion, and 2 with heterozygous ß-thalassemia 3.5-kb gene deletion. RESULTS: HRM analysis indicated that the amplified fragments from α-thalassemia-1 SEA type deletion, α-thalassemia-1 Thai type deletion, ß-thalassemia 3.5-kb gene deletion, and the wild-type ß-globin gene had specific peak heights at mean melting temperature (T(m)) values of 86.89â, 85.66â, 77.24â, and 74.92â, respectively. The results obtained using single-tube multiplex real-time PCR with SYBR Green1 and HRM analysis showed 100% consistency with those obtained using conventional gap-PCR. CONCLUSIONS: Single-tube multiplex real-time PCR with SYBR Green1 and HRM analysis is a potential alternative for routine clinical screening of the common types of α- and ß-thalassemia large gene deletions, since it is simple, cost-effective, and highly accurate.
Subject(s)
Asian People/genetics , Gene Deletion , Organic Chemicals/chemistry , Polymerase Chain Reaction/methods , alpha-Thalassemia/genetics , beta-Thalassemia/genetics , Asia, Southeastern , Benzothiazoles , Diamines , Genotype , Humans , Phase Transition , Quinolines , Reagent Kits, Diagnostic , Thailand , Transition Temperature , alpha-Thalassemia/diagnosis , beta-Thalassemia/diagnosisABSTRACT
The ß-chain hemoglobin (Hb) variants interfere with the diagnosis of ß-thalassemia trait using high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). We analyzed the effect of Hb Hope, a ß-chain Hb variant frequently found in the Thai population, on ß-thalassemia trait diagnosis. HPLC and CE were used to quantify the level of HbA(2) in 11 whole blood samples containing Hb Hope. The levels of Hb Hope detected by both methods were similar. An elevated HbA(2) level was found in all samples analyzed by the CE method, while 1 was increased when analyzed by HPLC, which was a compound heterozygous of Hb Hope and α-thalassemia-1 SEA-type deletion. Of 11 samples, 6 had mean corpuscular volumes within the reference range. All samples showed negative results for molecular analysis of ß(0)-thalassemia codon 17, 41/42, and 71/72 mutations and ß-thalassemia 3.5-kb deletion. Therefore, Hb Hope interfered with the diagnosis of ß-thalassemia trait analyzed by CE but not by HPLC.
