Probabilistic post-processing of short to medium range temperature forecasts: Implications for heatwave prediction in India.

Accurate and reliable air temperature forecasts are necessary for predicting and responding to thermal disasters such as heat strokes. Forecasts from Numerical Weather Prediction (NWP) models contain biases which require post-processing. Studies assessing the skill of probabilistic post-processing techniques (PPTs) on temperature forecasts in India are lacking. This study aims to evaluate probabilistic post-processing approaches such as Nonhomogeneous Gaussian Regression (NGR) and Bayesian Model Averaging (BMA) for improving daily temperature forecasts from two NWP models, namely, the European Centre for Medium Range Weather Forecasts (ECMWF) and the Global Ensemble Forecast System (GEFS), across the Indian subcontinent. Apart from that, the effect of probabilistic PPT on heatwave prediction skills across India is also evaluated. Results show that probabilistic PPT comprehensively outperform traditional approaches in forecasting temperatures across India at all lead times. In the Himalayan regions where the forecast skill of raw forecasts is low, the probabilistic techniques are not able to produce skillful forecasts even though they perform much better than traditional techniques. The NGR method is found to be the best performing PPT across the Indian region. Post-processing Tmax forecasts using the NGR approach was found to considerably improve the heatwave prediction skill across highly heatwave prone regions in India. The outcomes of this study will be helpful in setting up improved heatwave prediction and early warning systems in India.

Analytical and clinical performance evaluation of enhanced chemiluminescence-based fourth-generation HIV combo assay: Report from tertiary health-care setup in North India.

INTRODUCTION: HIV fourth-generation assay, designed for the detection of HIV p24 antigen along with anti-HIV antibodies of both immunoglobulin M and immunoglobulin G type against HIV 1 and HIV 2 viral antigens, have helped in the early detection of HIV infection and supports in minimizing the transmission risk in the acute phase of infection. The objective of this study was to evaluate the analytical and clinical performance of HIV fourth-generation assay based on enhanced chemiluminescence technology. MATERIALS AND METHODS: The analytical performance of the assay was evaluated in terms of accuracy, precision, limit of detection, type of sample (serum vs. plasma), cross-reactivity (with other transfusion transmissible infections markers), and interference (with endogenous substances). Proficiency control material included kit-controls, archived known positive donor samples, third-party controls, and World Health Organization (WHO)/National Institute for Biological Standards and Controls (NIBSC, MHRA, UK) controls. The clinical performance was evaluated using routine donor and patient samples received during the study period. RESULTS: HIV fourth-generation assay showed reliable and reproducible results measured in terms of coefficient of variation % with kit-controls, archived known positive donor samples, third-party controls, and WHO international standards for anti-HIV 1 and 2 antibodies, HIV1 p24 antigens and HIV2 p26 antigen controls. The analytical sensitivity of the HIV fourth-generation assay was found to be 0.1 IU/mL of HIV1 p24 antigen control and there was no cross-reactivity or interference observed. In the clinical performance of the assay, HIV fourth-generation assay showed reliable performance in both donor and patient samples. CONCLUSION: HIV fourth-generation assay meets the requirements for its use as a screening assay for HIV infection based on the analytical and clinical performance of the assay.

Immuno-hematological consequence of intravenous drug abuse?

Intravenous (IV) drug abuse has been well established to be the source of transfer of infections, such as HIV, hepatitis C virus, and hepatitis B virus. However, often overlooked fact is that IV drug abusers have a potential for developing alloimmunization due to universal practice of flushing/washing out the syringe by own blood to rinse out the drug in the syringe. We present here a case of a 28-year-old man who presented with a rather unique predicament of having developed four different alloantibodies after exposure to allogenic blood through IV drug abuse. This case was detected promptly due to routine usage of type and screen policy for all the patients receiving transfusion. Such screening for atypical antibodies must be instituted to preemptively identify these antibodies and arrange compatible blood, which could have been difficult otherwise, at short notice during routine crossmatch. This is the first of its kind case ever reported from India and has no precedence.

Applying Donath-Landsteiner test for the diagnosis of paroxysmal cold hemoglobinuria.

61-year old male patient was admitted to the hospital with clinical picture of hemolytic anemia with hemoglobinuria. Patient was suspected to have Infectious Mononucleosis (IM) with Auto Immune Hemolytic Anemia (AIHA). DAT was positive with anti-C3d specificity. Donath Landsteiner (DL) test was positive; confirming Paroxysmal Cold Hemoglobinuria (PCH). The final diagnosis was IM with PCH. Patient was managed conservatively and discharged after seven days. DL test specifically detects a biphasic autoantibody (IgG type) that binds to RBCs at cold temperatures, and fixes complement on the RBC membrane. However RBCs are only lysed upon warming to 37C when complement cascade proceeds to completion.

An algorithmic approach to serological work-up of ABO sub-groups which present as ABO discrepancies in resource constraint settings.

BACKGROUND: ABO subgroups or weaker variants of A or B are group A or B subjects whose erythrocytes give a weak or negative reaction serologically with anti-A or Anti - B antisera respectively. Occurrence of these subgroups may lead to an ABO discrepancy which often puts transfusion services in a quandary. ABO subgroups which present as ABO discrepancies can be missed if reverse grouping is not performed. AIM: This study was planned to estimate the prevalence of different subgroups which can present as an ABO discrepancy in Indian population, and provide an insight to transfusion services for identification of subgroups serologically. MATERIALS AND METHODS: A cross-sectional, analytical study was performed at a tertiary healthcare based blood bank on whole blood donors and patients from January 2017 to July 2018. All suspected type II and Type IV (with Anti-A1) ABO discrepant samples were projected to an algorithmic testing process, to confirm discrepancy and then narrow down to the probable subgroup. RESULTS: A total of 33 subgroup discrepancies; 26 of A group and 7 of B group were identified out of 73,380 patient and 35,279 donor samples tested for blood grouping. Following the algorithm, the overall prevalence of weak subgroups which can present as an ABO discrepancy was found to be 1 in 3293 or 0.03% in our population by serological testing. Out of the discrepancies caused by subgroups, the prevalence of subgroups of A were 0.0101%, 0.0018%, 0.0009%, 0.0027%, 0.0027% and 0.0018% for A2 with anti-A1, A3, Aend, Ax, Am and Ael respectively while those of B were 0.009%, 0.0009%, 0.0009% and 0.009% for B3, Bx, Bm and Bel respectively. CONCLUSION: Algorithmic approach for resolution of ABO discrepancies caused by subgroups helps in identifying the subgroup which is important because these individuals may be mistyped as group O individuals.

Routine indirect antiglobulin testing of blood donors-a further step toward blood safety: an experience from a tertiary care center in northern India.

CONCLUSIONS: This scientific article emphasizes the importance of a policy for antibody screening of all blood donors as a step to further improve blood safety. We also report the incidence of red blood cell (RBC) alloimmunization in healthy blood donors obtained using a cross-sectional prospective study from September 2017 to January 2019 in the Department of Transfusion Medicine of a tertiary care referral and teaching institute in northern India. The indirect antiglobulin test (IAT) for unexpected RBC antibodies was performed by the conventional tube test with pooled group O RBCs on all donor units irrespective of their D status. Samples with positive IATs were sent to the Immune Hematology Reference Laboratory for further immunohematolo-gy workup, maintaining predefined optimal storage and transport conditions. Of the 10,390 donors studied, 9959 were males and 431 were females. The incidence of unexpected antibodies (antibodies other than those of the ABO blood system) among the blood donors was found to be 0.18 percent (19 of 10,390 with 25 alloantibodies). Of the 19 alloimmunized donors, 16 (84.2%) were male (alloimmunization rate 0.16%, 16 of 9959) and 3 (15.8%) were female (alloimmunization rate 0.69%, 3 of 431) (p = 0.01; chi-square test). In our study, the most frequent alloantibodies identified were of the Lewis blood group system (17 of 25 [68%] in 14 of the 19 alloimmunized donors). The second most common allo-antibodies belonged to the Rh blood group system (4 of 25 [16%] in 3 of the 19 alloimmunized donors), followed by those of the MNS blood group system (3 of 25 [12%] in 2 of 19 alloimmunized donors). Anti-K was found in one donor (1 of 25 [4%]). Based on the results of the study, we recommend that a policy of routinely performing IATs on all donor units, irrespective of their D status, be adopted as an essential component of safe blood transfusion practices.

Severe hemolytic disease of the fetus and newborn due to anti-E and anti-Jka.

CONCLUSIONS: Red blood cell alloimmunization to antigens other than D, such as C, c, E, e, and antigens in the Kell, MNS, and Duffy blood group systems, has emerged as an important cause of hemolytic disease of the fetus and newborn (HDFN). Antibody screening for these antibodies is not routinely practiced for all antenatal patients in developing countries, mainly because of financial constraints. Here we report a rare case of HDFN due to dual antibodies to Rh and Kidd blood group system antigens: anti-E and anti-Jka. This case report highlights the importance of routine and regular antenatal screening of all pregnant women for proper monitoring and follow-up.

The frequent and the unusual red cell phenotypes in Indian blood donors: A quest for rare donors.

A clinically significant red cell alloantibody is capable of accelerated destruction of red cells bearing the corresponding antigen. Knowledge of prevalence of these antigens is necessary for performing day to day work and for research in immunohematology. The primary aim of this study was to find the prevalence of 18 clinically significant blood group antigens in blood donors. Secondary objectives were to motivate and create a database of accessible, volunteer O blood group donors and to register rare donors with existing registries. A cross-sectional observational study was conducted in the department of Transfusion Medicine at a large tertiary care hospital in India from October 2016 to May 2018 with a planned sample size of 4800. Study population included healthy blood donors of either gender coming for blood donation to the blood centre. A total of 6678 samples were included in the study. First time donors were 21.41 % while 78.59 % were repeat donors. Voluntary donors constituted 15.81 % while replacement donors were 84.19 %. Male donors were 89.82 % while female donors were 10.18 %. The antigen, phenotype and gene frequencies were calculated. An extended phenotyped voluntary donor database was created and four rare donors were identified. One of these rare donors was registered with the International Rare Donor Panel (IRDP) and rest were registered in a local registry. This study might help enhance the confidence of blood banks in finding appropriate units for patients with unexpected antibodies or with rare phenotypes. It also paves a way for registering rare donors locally and internationally.

Comparison of a column agglutination technology-based automated immunohematology analyzer and a semiautomated system in pretransfusion testing.

INTRODUCTION: Semi-automated equipment using Column agglutination technology (CAT) is widely used where centrifugation and incubation are automated but substantial amount of the work is still executed manually. Larger laboratories are moving towards automation to eliminate errors, reducing exposure to bio-hazardous samples, assuring traceability, reliability, turnaround time (TAT) and throughput. Moving towards automation and greater reliability, we therefore, decided to install an automated immunohematological (IH) analyzer "Vision". In this study we evaluated reliability and performance before clearing "Vision" for routine use. MATERIALS AND METHODS: Study was conducted in the Department of Transfusion-Medicine. The primary objective was to assess the reliability of results and compare with routine use semi-automated BIOVUE system (Reference system). Secondary objective was to evaluate the performance (TAT and throughput) of the Vision to handle routine and emergency workload. RESULTS: Total of 1276 known samples were used to assess 2640 pre-transfusion tests (1229 ABO/Rh D typing; 1229 antibody screening; 54 antibody identification; 86 crossmatch and 42 DAT). All 1229 ABO Rh typing results were concordant between the two systems. Overall agreement between the Vision IH analyzer and reference system for ABO Rh typing was 99.95%. All antibody screening, crossmatch and DAT results were concordant between the two systems. TAT of Vision was substantially shorter than the reference system for all test profiles. CONCLUSION: Based on study results, Vision was approved for routine use in laboratory. It was found to be reliable with considerably shorter TAT and capable of handling high throughput of immunohematological tests.

Applications of selected cells in immunohematology in a developing country: case studies.

CONCLUSIONS: When an antibody is detected, its specificity should be determined and its likely clinical significance should be assessed. When one antibody has been identified, it becomes necessary to confirm the presence of additional significant antibodies to ensure that compatible blood is provided to the patient. To perform this confirmation, specific reagent red blood cells (RBCs) are selected; these are called selected cells. Though the most common use of selected cells is for antibody confirmation, they can also be used for several other immunohematologic applications. In a developing country like India, the performance of antibody screening for unexpected antibodies on a routine basis is a comparatively new phenomenon, and those laboratories performing advanced immunohematologic testing would need to use selected cells to arrive at an accurate conclusion. This report defines selected cells and enumerates sources of these RBCs. Detailed immunohematologic applications are discussed with applicable case studies.

Alloimmunization in autoimmune hemolytic anemia patient: The differential adsorption approach.

Patients of ß-thalassemia major are dependent on regular blood transfusions for their entire lifetime. Development of antibodies against red blood cell (RBC) antigen which may be alloantibody or autoantibody, several times as a result of frequent red cell component transfusions, further complicates the subsequent transfusion therapy. Among the autoantibodies, warm-reactive autoantibodies are commoner and interfere in the pretransfusion testing. These RBC autoantibodies present in patient's serum potentially react with all the cells of antibody identification panel giving "pan-reactive" picture and making alloantibody identification complex. In this report, we present our approach in a thalassemia patient who presented with warm-type autoimmune hemolytic anemia, low hemoglobin of 5.8 g/dl, and three significant alloantibodies (anti-D, anti-S, and anti-Jkb) which were masked by pan-reactive warm autoantibody(s). Differential adsorption was used to unmask underlying alloantibodies. We suggest that differential adsorption procedure is an effective and efficient method for autoantibody adsorption, detection, and identification of masked alloantibody(s), especially in patients with low hemoglobin and history of recent blood transfusion.

Allo-antibody identification: a software approach!

BACKGROUND: Unexpected allo-antibody identification is difficult serological test requiring in-depth knowledge of antibody behavior, identification rules, knowledge of zygosity of antigens and dosage phenomenon. Software which uses an algorithm based on characteristics of antibodies is now available to interpret specificity of allo-antibody. A study was undertaken to evaluate the effectiveness of one such software (Resolvigen) for antibody identification compared with manual antibody identification method. MATERIALS AND METHODS: The study was a retrospective observational study where 238 allo-antibody results were re-evaluated using Resolvigen software (Ortho Clinical Diagnostics, Johnson and Johnson, Raritan, NJ, USA) and agreement between manual and software approaches was studied. Resolvigen software was also evaluated for usefulness, ease of use and predicted future usage by administering investigators a questionnaire with Likert scale. RESULTS: Agreement between the results of manual and automated methods ranged from 98.6% for single antibody to 65% for two antibodies (p = 0.000). Resolvigen software came out as very useful, easy to use, and with high predicted future usage. CONCLUSION: This study concludes that Resolvigen can either replace manual method or be used as adjuvant to routine manual method.