Screening for thalassemia and hemoglobinopathy in a rural area of Thailand: a preliminary study.

The present study aimed to screen thalassemia and hemoglobinopathy in Baan Na-Ngam, Chachoengsao Province, Thailand. Blood samples were obtained from 266 volunteers; 105 males and 161 females aged 7 to 49 years. Blood samples screened for thalassemia combining the OF and modified DCIP precipitation tests. CBC, RBC indices, hemoglobin typing, HbA2 and Hb E were determined. Combined OF and DCIP tests found that in normal subjects, 128 out of 155 were negative for both, 3 were -/+ pattern, 22 were +/- pattern and 2 was positive for both. Interestingly, one sample showed an abnormal hemoglobin pattern, which could not be determined by automated LPLC. Three beta-thalassemia trait subjects were positive for only the OF test. For the Hb E trait, 57 out of 94 were -/+ pattern; 37 were positive for both tests. Moreover, 14 homozygous Hb E subjects were positive for both tests. The prevalence of beta-thalassemia trait was 1.1%, Hb E trait was 35.3% and homozygous Hb E was 5.3%. Since DNA analysis was not performed, alpha-thalassemia1 and alpha-thalassemia2 traits cannot be excluded. In conclusion, a combination of the OF and DCIP tests is suitable for preliminary screening for thalassemia and hemoglobinopathy. However, RBC parameters, hemoglobin typing and PCR analysis will provide more specific diagnosis, especially in alpha-thalassemias.

The gel test: twelve-year's experience in Thailand.

Within twelve years of its introduction for blood group serology testing in the blood bank, the gel test has gained widespread usage throughout Thailand, especially for antibody screening, crossmatching, direct antiglobulin testing and blood group antigen typing. The gel test has been proven to be more sensitive than the standard conventional tube test. Furthermore, the test itself is simple and practical for mass screening and application in emergency situations.

Use of the gel test to follow up chimerism in ABO mismatched bone marrow transplantation patient: a case report.

OBJECTIVE: The authors report here our experience using the gel test to follow up chimerism in a 5 year old girl with beta thalassemia/Hemoglobin E disease (beta thal/HbE), post allogeneic bone marrow transplantation with Hb E trait HLA identical sibling donor. They were ABO blood group major mismatched donor-recipient pairs (donor and recipient blood group are B and O, respectively). MATERIAL AND METHOD: Pre and post transplanted EDTA blood samples from the girl with beta thalassemia/ Hemoglobin E were tested for ABO, Rh and direct antiglobulin test (DAT) using the A-B-AB-D-ctl/ AHG card and the titer of anti-A and anti-B were tested by the conventional tube technique. The sex chromosome study and hemoglobin typing were also examined. RESULTS: In this technique, mixed field agglutination is clearly identified from positive and negative results. The authors detected peripheral recovery, mixed O/B population after transplantation on day +26 with positive DAT. The DAT was negative on day +67 after transplantation and the recipient blood group was completely changed to B on day +123. In addition, Hb typing was changed to Hb E trait with Hb F less than 5 % on day +37. The engraftment of neutrophils, more than 5x10(9)/L, was detected on day+14 and platelet count was more than 20x10(9)/L on day +28. On day +90, the patient was transfusion-independent with the mean Hb level at 11.4 g/dL (10.4-13.1). The sex chromosome and hemoglobin typing were changed to the donor on day +300. CONCLUSION: The gel test is an alternative method which is simple and helpful in detecting mixed red blood cell populations, particularly in the ABO or other blood group mismatched bone marrow transplantation.

Laboratory approach in Thai patients with venous thrombosis.

This retrospective study aimed to analyze laboratory findings in Thai patients with venous thrombosis in Phramongkutklao Hospital from August 1997 to October 2004. Blood samples obtained from 166 patients with ages ranging from 10 months to 87 years were tested for protein S (PS), protein C (PC), antithrombin (AT), factor V Leiden (FVL) and prothrombin G20210A. It was found that low levels of PS, PC, and AT were observed in 23 patients (13.9%), 21 patients (12.7%) and 11 patients (6.6%), respectively. The incidence of combined low levels of anticoagulant factors occurred in 23 patients (13.9%). Three patients (1.8%) were positive for FVL. All patients were negative for prothrombin G20210A. Additionally, 85 patients (51.2%) were negative for all tests. In conclusion, it is recommended that the screening tests for anticoagulant factors PS, PC and AT be used to investigate the causes of thrombosis in Asian populations due to their cost-effectiveness. However, the detection of gene mutations inducing thrombosis should be considered.

Dyslipidemia in Thai rural adults.

The present study aimed to determine the prevalence of dyslipidemia in adults in a rural area of Thailand. Random sampling was conducted in 443 volunteers, 187 males and 256 females, aged > or = 35 years in Chachoengsao Province. After a 12-hour fast, the blood was drawn for the analysis of total cholesterol, triglycerides, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol. Mean serum lipids of cholesterol, LDL cholesterol, HDL cholesterol and triglycerides were 207.79 +/- 46.98, 117.26 +/- 36.59, 50.53 +/- 2.14 and 201.21 +/- 131.07 mg/dL, respectively. Nineteen percent of them had cholesterol > or = 240 mg/dL and 10% had LDL cholesterol > or = 160 mg/dL. Seven percent had HDL cholesterol < or = 35 mg/dL. However, LDL/HDL cholesterol ratios > 5, were found in only 0.9%. In conclusion, the prevalence of dyslipidemia was high in rural Thai adults. Further surveillance in this population is essential in verifying the impact of dyslipidemia as a risk of cardiovascular disease in rural Thai adults.

Rapid screening of PNH red cell populations using the gel test.

Paroxysmal nocturnal hemoglobinuria (PNH), an acquired clonal hematopoietic stem cell defect is underdiagnosed because of its atypical symptoms in some patients and because available methods, which are time consuming and complicated, are not widely used. The purpose of this study is to compare the results of the detection of PNH red cell populations using the PNH gel test and the Ham test. Fifty-eight blood samples obtained from 35 patients and 23 healthy blood donors were tested for PNH by the PNH gel test and the Ham test. It was found that 7 (20%) of the patients were positive for PNH by both tests. Twenty-three blood samples from healthy donors were all negative for PNH by both tests. The overall sensitivity and specificity of the gel test were 100%. This study showed that the PNH gel test was simple and could replace the Ham test as a screening test for PNH. This test would be especially easy to introduce in laboratories that are already using this system for blood grouping and antibody detection.

Factor V Leiden and prothrombin G20210A mutations in Thai patients awaiting kidney transplant.

Renal transplantation provides the best long-term treatment for chronic renal failure, but thrombosis of the transplanted renal artery or renal vein is one of the causes of kidney failure in the early postoperative period. Factor V Leiden (FVL) and prothrombin G20210A mutation are the most frequent genetic abnormalities associated with venous thrombosis. We investigated the prevalence of FVL and prothrombin G20210A by polymerase chain reaction with restriction fragment length polymorphism in 75 Thai patients awaiting renal transplant, and a control group of 106 healthy blood donors. Of those awaiting renal transplant, none was found to carry FVL or prothrombin G20210A mutations. Neither the heterozygous nor the homozygous FVL mutation nor the prothrombin G20210A mutation was detected in the 106 healthy volunteers. Although we failed to detect FVL and prothrombin G20210A mutation among those waiting for a kidney transplant, the population size was small. Further studies need to be performed in order to ascertain if these coagulation mutations are of relevance in predicting patients at risk of early transplant failure.

Distribution of blood group systems in Thai blood donors determined by the gel test.

The rapid availability of fully typed donor blood is of great advantage, especially for patients requiring repeated blood transfusions. Only limited blood group antigen typing has been carried out using the conventional tube technique. This study aimed to examine the distribution of blood group systems in Thai blood donors by the gel test. The ABO, Rh, MNSs, Duffy, Lewis, P, Kell, Lutheran and Kidd blood groups were examined in 500 Thai blood donors by the gel test. The distribution of blood group systems using the gel test was compared with other studies in the Thai population. Results : For the ABO System, group O was the most common (42.6 %) followed by group B (30.8 %), group A (20.2 %) and group AB (6.4 %). The most common Rh gene complex was CCDee (53.8 %) which was similar to other studies. The MMss and MNss gene complexes were the most common in the MNSs System. Fya was very common as in other Asians. In the Lewis System, the incidence of Le (a-b-) was 21.0 %, which is consistent with other findings in the Thai population. One hundred and forty-five (29 %) were positive for anti-P1. For the Kell System, 1 out of 500 (0.2 %) had the Kk type, 99.8 % had the kk types and only Kpb positive types were observed in this study, as well as Lu (a-b+) in the Lutheran System. The Jk (a-b-) was not found since it is a rare phenotype among Thai people. Discussion : This study shows the blood group distribution in 500 Thai volunteers using the gel test. Because of its simplicity and efficacy, this test is practical in population studies. Additionally, it is useful for mass screening and can be applied in emergency situations.