A multicenter prospective observational study on the use of type and screen method versus conventional type and crossmatch policy for pre-transfusion testing in the Indian population

Despite knowing the benefits of the type and screen (TS) method in pre-transfusion testing (PTT), most transfusion centers in developing countries continue to be reluctant to adopt a TS strategy over the conventional type and antihuman globulin (AHG) crossmatch (TX) policy in their routine laboratory practice because of the cost of obtaining antibody screening reagents. To generate strong evidence, this multicenter, observational study was conducted in which we collected data prospectively over a 1-year period from six major blood centers in India. The primary objective of this study was to identify the discordance between TS and TX results. A secondary objective was to identify the allo-antibody specificity in patients with positive antibody detection tests. All patients with orders for red blood cell transfusion who met patient selection criteria were subjected to parallel testing by column agglutination technology (CAT) for both the antibody detection test (screen) using a commercial three-cell panel and for the AHG crossmatch. A total of 21,842 patients were tested. In 148 patients with incompatible crossmatches, samples from six patients gave negative results with the antibody detection test, whereas the antibody detection test was positive in samples from 118 patients among the 21,694 crossmatch-compatible cases. The TS approach achieved a positive percent agreement of 95.95 and was found to be significantly effective in preventing the transfusion of serologically incompatible blood. The risk associated with abbreviating the AHG crossmatch was found to be 0.009 percent. Most of the identified clinically significant alloantibodies were directed to Rh antigens (D>E>c>C>e), followed by anti-K and anti-M. This study has generated sufficient robust data for the Indian population by including patients from all major geographical areas of the country and concluded a satisfactory agreement level as well as non-inferiority to the current PTT policy. Therefore, TS policy can be implemented in developing countries with no compromise on blood safety, provided sufficient technical and infrastructural support are available.

Pooled platelet product using the Acrodose plus system: evaluation of feasibility, safety and efficacy

BACKGROUND

Pooling of whole blood-derived platelets is not practiced in India. Currently available data shows that pooled platelets are equivalent in quality and less costly when compared with apheresis platelets.

AIM

To evaluate feasibility, safety and efficacy of pooled platelets using the Acrodose Plus system.

MATERIAL AND METHODS

Standardization of platelet pooling procedure was done. Sterile docking device was used to maintain closed system. Pools of ABO compatible platelets (N=40) as well as ABO incompatible (N=10) pooled platelets were studied. ABO antibody titers were studied before and after pooling in case of ABO incompatible platelet pools. Corrected count increments (CCIs) (at 1h and 24h) were noted after transfusion of pooled platelets and Apheresis platelets in matched patient groups.

RESULTS

Loss of platelet product due to pooling and leucodepletion was not statistically significant (p=0.23). Leucodepletion >3 log was achieved in all pooled platelets. The total platelet content, time taken for procedure and pH were within acceptable limits. There were no issues related to platelet availability and turn around time during the study period. There was a reduction in the ABO antibody titers after pooling in case of the ABO incompatible pools. None of the pooled platelets showed evidence of bacterial contamination on testing with eBDS system at 18 h and 24h intervals after pooling. CCI with pooled platelets was equivalent to that with apheresis platelets at 1h (p=0.36) and 24h (p=0.15).

CONCLUSION

Whole blood derived platelets can be pooled safely using closed system without altering the platelet quality in vitro as well as in vivo survival post transfusion. Pooled platelets can be a cost effective and safe alternative to thrombocytopenic patients whose transfusion requirements cannot be fulfilled with apheresis platelets alone.

Red cell hemolysis during processing and storage

INTRODUCTION

Apart from the visual assessment, measurement of plasma hemoglobin in the supernatant from red cell units provides an objective measure of the extent of hemolysis during storage.

STUDY DESIGN AND METHODS

Packed red cells (N=50), 25 units each in triple (CPD-A1 and SAGM) and quadruple (CPD-A1 and ADSOL) blood bags were evaluated for plasma hemoglobin by the tetramethylbenzidiene (TMB) method on day 1, 7, 14, 21 and 28 of collection. The hemoglobin, hematocrit, MCV, LDH and potassium levels were also noted. Whole blood units (N=25) were used as controls.

RESULTS

Hemolysis increased in all the stored red cell units. Plasma hemoglobin increased significantly in the first week of storage. The hemolysis, LDH and potassium levels were found to be significantly higher in the red cell units harvested from the triple blood bags. However, on day 28 of storage, free hemoglobin in all the red cell units was much below the 0.8% hemolysis.

CONCLUSION

Hemolysis of the red cells increases due to processing and during storage and is maximum during the first week. Adequate process control and proper storage facilities should be ensured to minimize the hemolysis of red cells during processing and storage.

Inventory management

A critical aspect of blood transfusion is the timely provision of high quality blood products. This task remains a significant challenge for many blood services and blood systems reflecting the difficulty of balancing the recruitment of sufficient donors, the optimal utilization of the donor's gift, the increasing safety related restrictions on blood donation, a growing menu of specialized blood products and an ever-growing imperative to increase the efficiency of blood product provision from a cost perspective. As our industry now faces questions about our standard practices including whether or not the age of blood has a negative impact on recipients, it is timely to take a look at our collective inventory management practices. This International Forum represents an effort to get a snap shot of inventory management practices around the world, and to understand the range of different products provided for patients. In addition to sharing current inventory management practices, this Forum is intended to foster an exchange of ideas around where we see our field moving with respect to various issues including specialty products, new technologies, and reducing recipient risk from blood transfusion products.

Red cell hemolysis during processing and storage

INTRODUCTION

Apart from the visual assessment, measurement of plasma hemoglobin in the supernatant from red cell units provides an objective measure of the extent of hemolysis during storage.

STUDY DESIGN AND METHODS

Packed red cells (N=50), 25 units each in triple (CPD-A1 and SAGM) and quadruple (CPD-A1 and ADSOL) blood bags were evaluated for plasma hemoglobin by the tetramethylbenzidiene (TMB) method on day 1, 7, 14, 21 and 28 of collection. The hemoglobin, hematocrit, MCV, LDH and potassium levels were also noted. Whole blood units (N=25) were used as controls.

RESULTS

Hemolysis increased in all the stored red cell units. Plasma hemoglobin increased significantly in the first week of storage. The hemolysis, LDH and potassium levels were found to be significantly higher in the red cell units harvested from the triple blood bags. However, on day 28 of storage, free hemoglobin in all the red cell units was much below the 0.8% hemolysis.

CONCLUSION

Hemolysis of the red cells increases due to processing and during storage and is maximum during the first week. Adequate process control and proper storage facilities should be ensured to minimize the hemolysis of red cells during processing and storage.

Evaluation of hemoglobin of blood donors deferred by the copper sulphate method for hemoglobin estimation

INTRODUCTION

The copper sulphate (CuSO4) specific gravity test for Hb screening tends to give inappropriate failures. This prompted us to compare it with alternate screening methods.

AIM

To study the impact of inaccuracy of CuSO4 method on donor deferral.

METHODS

Capillary and venous blood samples of 400 potential blood donors failing the primary Hb screening using appropriately standardized CuSO4 test (specific gravity 1.053) were tested by Hemocue photometer, the Hb colour scale, Cyanmethemoglobin method as well as the automated hematology analyser, which was considered as the standard reference method.

RESULTS

One hundred and sixteen donors (29%) who failed the CuSO4 test had true Hb levels >12.5 g/dl. The Hb levels of 131 (32.8%) deferred donors were between 12 and 12.5 g/dl. The sensitivity of Hemocue, Hb colour scale and Cyanmethemoglobin was 99%, 97% and 96% and their specificity was 45%, 93% and 46%, respectively. The positive predictive values (PPV) of Hemocue and Cyanmethemoglobin methods were low (43% and 44%, respectively) but their negative predictive values (NPV) were high (99%, and 97%, respectively). The Hb colour scale had an overall best performance with a PPV of 96% and NPV of 95%.

CONCLUSION

The Hemoglobin colour scale which is inexpensive, convenient for field testing and has the overall best performance, is the most suitable for donor Hb screening. Since its readability is 12 g/dl, lowering the donor Hb threshold to 12 g/dl should be actively considered.

Correlation of CD34+ cell yield in peripheral blood progenitor cell product with the pre-leukapheresis cell counts in peripheral blood

INTRODUCTION

Accurate timing of the leukapheresis procedures is of paramount importance to get the best possible CD34+ cell yield in the minimum number of leukapheresis procedures.

AIM

To find if pre-harvest CD34+ cell concentration in peripheral blood correlates with CD34+ cells in the product.

MATERIAL AND METHODS

Sixty Leukapheresis procedures were performed for 25 patients (8 autologous and 17 allogeneic transplants) with hematological malignancies. Statistical analysis was performed to correlate the pre-harvest CD34+ cell count and the CD34+ cell yield. Volume processed during PBPC harvests was three times the blood volume.

RESULTS

The best correlation was found between the leukapheresis product CD34+ cell count and the pre-harvest PB-CD34+ cell count (PCC=0.674) when compared with the other pre-harvest PB cell counts viz., WBC (PCC=0.229) and MNC (PCC=0.324). This correlation was better in the allogeneic harvest (PCC = 0.645) than the autologous harvest procedures (PCC = 0.348). Correlation analysis based on paired samples from the 60 leukapheresis procedures showed that when the pre-leukapheresis PB-CD34+ cell count was >20x10(3)/ul a yield of >1x10(6) CD34+ cells/Kg could be obtained in 95% of the cases and >2x10(6) CD34+ cells /Kg could be harvested in 68% of cases whereas when the pre-leukapheresis PB-CD34+ cell count was <5x10(3)/microl the yield was <1x10(6) CD34+ cells/Kg in 81% of the procedures.

CONCLUSION

The yield of CD34+ cells in PBPC harvests depends on the pre-harvest CD34+ cell concentration and therefore it is more useful than the pre-harvest WBC or MNC counts for predicting the appropriate timing of the harvests and also to achieve the best possible yield of CD34+ cells.

Plasma exchange for thrombotic thrombocytopenic purpura following hematopoietic stem cell transplantation

A 17 years old female diagnosed with acute myeloid leukemia (AML)-M2 received an allogeneic haematopoietic stem cell transplant (HSCT) and was given graft versus host disease (GVHD) prophylaxis with methotrexate, cyclosporin-A (CsA) and methyl prednisolone. On day +42 post-transplant, she was diagnosed to have thrombotic thrombocytopenic purpura (TTP). Therapeutic plasma exchange (TPE) (40 ml/kg body mass) using fresh frozen plasma was performed on 8 consecutive days. The renal function, LDH levels, platelet count and peripheral smear findings improved but the neurological symptoms persisted even after TPE. Few reports are available in literature on the effectiveness of therapeutic plasma exchange (TPE) in post-bone marrow transplant (BMT) TTP. The good hematologic response achieved in this patient suggests that TPE could be life-saving and should be tried in every patient with post-BMT TTP.