Panutsaya Tientadakul

Homozygous hemoglobin Tak causes symptomatic secondary polycythemia in a Thai boy.

Secondary polycythemia caused by high-oxygen-affinity hemoglobin is rare in children. Most patients with this condition have asymptomatic erythrocytosis. In this article the authors describe a young boy from Thailand with plethora, hypoxemia, and aggravated respiratory distress following a chest infection. Hematological and molecular studies revealed that the boy is homozygous for Hb Tak, an extended &bgr;-globin variant with high oxygen affinity. This report of a patient who is homozygous for high-oxygen-affinity hemoglobin highlights the clinical significance of this hemoglobin disorder, which has been previously reported in several unrelated families from Southeast Asia.

Detection of haemoglobin variants and inference of their functional properties using complete oxygen dissociation curve measurements

Complete oxygen dissociation curves for red cell suspensions of three haemoglobinopathies, namely haemoglobin (Hb) H, Hb Köln and Hb Tak/β thalassaemia diseases, were measured using automatic recording methods. These curves were left‐shifted compared with the normal red cell curve and showed a biphasic shape as a result of co‐existence of the high and normal affinity haemoglobin components. Computer‐assisted simulation of these biphasic curves enabled us to infer the curves for the pure abnormal haemoglobins and their fraction in the total haemoglobin of the red cell. The inferred values of fraction agreed with those determined by haemoglobin type analysis or the literature values. The curve for Hb Köln red cells deviated from the normal red cell curve in the whole range of oxygen saturation, whereas the curve for Hb H was close to the normal curve at the middle and upper portions. This difference in deviation was ascribed to a possible interaction between Hb Köln and Hb A through subunit exchange, and its absence between Hb H and Hb A. The present results indicate that measurement of the complete oxygen dissociation curve is important for the detection of non‐interacting variants such as Hb H and is useful for inferring the functional properties of haemoglobin components that are not easily isolated.

Inappropriate use of protein C, protein S, and antithrombin testing for hereditary thrombophilia screening: an experience from a large university hospital

Introduction:  Deficiencies of protein C, protein S, and antithrombin are the main inherited risk factors in Thai patients with venous thromboembolism, although the prevalence is not high.

Improvement of Coagulation Laboratory Practice in Thailand: The First-Year Experience of the National External Quality Assessment Scheme for Blood Coagulation

CONTEXT In Thailand until 2005 there had been no external quality assessment scheme at the national level for blood coagulation tests. Only a few laboratories had an external quality assessment for these tests. In the year 2005, the Thailand National External Quality Assessment Scheme for Blood Coagulation was founded. OBJECTIVES To describe the establishment of the Thailand National External Quality Assessment Scheme for Blood Coagulation (including problems encountered and solutions), its progression and expansion, and the improvement of coagulation laboratory practice in Thailand during 2 trial surveys and 4 formal surveys conducted in the first 1 1/2 years. DESIGN Between 2005 and 2006, the external quality assessment samples for prothrombin time/international normalized ratio and activated partial thromboplastin time were distributed to the participants as well as the instructions and suggestions for the improvement of laboratory practice. From the data collected, the all-method coefficient of variation of the international normalized ratio and activated partial thromboplastin time was calculated for each survey. RESULTS The number of participants increased during the first 1 1/2 years that the surveys were conducted, from 109 to 127. Survey data demonstrate an improvement in response rate and an increase in the number of laboratories that determine their own reference ranges and repeat this for every change of reagent lot, using the appropriate anticoagulant. The increased precision of tests is indicated by the decrease of the all-method coefficient of variation of the international normalized ratio and activated partial thromboplastin time. Examples of individual laboratory improvement through feedback are also described. CONCLUSIONS The improvement of coagulation laboratory practice both through the instructions provided and liaison with participants was observed during the course of this scheme.

Establishing an external quality assessment scheme for point‐of‐care international normalized ratio in Thailand

Effective warfarin therapy management has gained national interest, resulting in the increased use of point‐of‐care testing (POCT) for international normalized ratio (INR). External quality assessment (EQA) is recommended to ensure quality of the testing. CoaguChek XS and CoaguChek XS Plus are the only commonly available POCT INR monitors in Thailand. Therefore, Thailand NEQAS for Blood Coagulation initiated the scheme for POCT INR in 2013, including only hospitals using these devices.

Use of an automated coagulation analyzer to perform heparin neutralization with polybrene in blood samples for routine coagulation testing: practical, rapid, and inexpensive.

CONTEXT Heparin contamination in blood samples may cause false prolongation of activated partial thromboplastin time (aPTT) and prothrombin time results. Polybrene can neutralize heparin, but it affects coagulation by itself. OBJECTIVES To determine the optimal concentration of polybrene to neutralize heparin, to determine the suitable sequence of reagents for the neutralization method performed on the analyzer at the same time as prothrombin time and aPTT testing, and to detect the heparin contamination in blood samples for coagulation tests in our hospital using this method. DESIGN Various concentrations of heparin were added to 10 normal and 76 abnormal plasma samples to study the efficacy of polybrene. Two programs of reagent sequencing for aPTT with polybrene performed on the analyzer were tested. Samples suspected of heparin contamination according to our criteria were selected for neutralization during a 3-month period. RESULTS The optimal final concentration of polybrene was 25 μg/mL. Polybrene should be added after the aPTT reagent to minimize its interference effect. Even though results of prothrombin time and aPTT after neutralization did not equal those before the spike of heparin, the differences might not be clinically significant. Eighty-one of 4921 samples (1.6%) were selected for aPTT with the neutralization method, and the detection rate of heparin contamination was 84% (68 of 81), giving an overall incidence of 1.4% (68 of 4921). CONCLUSIONS This method is inexpensive and can be performed rapidly with prothrombin time and aPTT on the automated analyzer, which makes it easy to practice with no need for extra plasma volumes.

The Effects of Temperature and Relative Humidity on Point-of-Care Glucose Measurements in Hospital Practice in a Tropical Clinical Setting.

Background: Hospitals in tropical countries experience conditions that exceed manufacturer temperature and humidity limits for point-of-care (POC) glucose reagents. Our goal was to assess the effects of out-of-limits storage temperature, operating temperature, and operating humidity on POC glucose measurement reliability. Methods: Quality control measurements were performed monthly using glucose test strips stored under controlled conditions and in inpatient wards under ambient conditions. Glucose test strips were evaluated in groups organized by operating temperatures of 24-25 (group 1), 28-29 (group 2), and 33-34°C (group 3), and relative humidity (RH) of ≤70 (group A), ~80 (group B), and ~90% (group C). Results: Glucose results for different storage conditions were inconsistent. Measurements at higher operating temperatures had lower values with mean differences of −2.4 (P < .001) and −36.5 (P < .001) mg/dL (28-29 vs 24-25°C), and −3.6 (P < .001) and −37.4 (P < .001) mg/dL (33-34 vs 24-25°C) for low and high control levels, respectively. Measurements at higher RH had lower values with mean differences of −4.0 (P < .001) and −13.2 (P < .001) mg/dL (~80 vs ≤70% RH), and −5.8 (P < .001) and −16.6 (P < .001) mg/dL (~90 vs ≤70% RH) for low and high levels, respectively. Conclusions: High temperature and high RH decreased glucose concentrations for the POC oxidase-based system we evaluated. We recommend that individual hospitals perform stress testing, then determine if maximum absolute differences, which represent highest risk for patients, are clinically significant for decision making by using error grid analysis.

Current practices of bleeding time in a developing country: an alert for noncompliance with the standard procedures.

Bleeding time is still widely performed in many developing countries including Thailand. To generate an accurate result, the procedure should be complied with standard recommendations such as those from Clinical and Laboratory Standards Institute (CLSI) and World Federation of Hemophilia (WFH). The authors surveyed the current practices of bleeding time in Thailand in order to verify the practices that did not comply with the accepted standard.

Point-of-care glucose testing: on-site competency assessment

PURPOSE The purpose of this pilot paper is to use on-site assessment to determine common non-compliance in point-of-care (POC) glucose testing, deficiencies that should be improved by the POC team or emphasized in further training. DESIGN/METHODOLOGY/APPROACH Assessment forms for POC site and staff competency were developed and used for direct observation in four POC sites. Nurses were sampled in these sites. FINDINGS The on-site assessment demonstrated that initial operator training was insufficient. Only three of 15 nurses achieved a satisfactory score on the first assessment. In all nine participants who had been assessed at least twice improved their performance. In total, 16 (30 percent) of 53 competency items were not achieved, so these should be addressed during refresher training. Improved compliance with the checklist was observed in two of four POC sites. RESEARCH LIMITATIONS/IMPLICATIONS Medical students and residents also perform the test, so more representative samples are needed. PRACTICAL IMPLICATIONS The assessment of staff performance in the workplace with constructive input and POC site inspections to identify common deficiencies are recommended. Refresher trainings should be focussed on the deficiencies identified. SOCIAL IMPLICATIONS Assessing staff performance in the workplace with constructive input and POC site inspections to identify common deficiencies are recommended. Refresher trainings should focus on deficiencies. ORIGINALITY/VALUE This study involved directly observing POC site staff during glucose testing. The assessment forms were based on ISO 22870:2006 technical requirements.

Evaluation of Thrombi-Stat MC1 for whole blood and plasma international normalized ratio in comparison with a laboratory method

The precision and comparability of the international normalized ratio (INR) analyzed by the Thrombi‐Stat MC1 coagulation testing system were evaluated before using as a point‐of‐care testing.