Evaluation of a new rapid anti-HbF FITC assay, Trillium QuikQuant, for detection and quantitation of foetomaternal haemorrhage.

INTRODUCTION: This study evaluated a new product for flow cytometric foetomaternal haemorrhage (FMH) quantitation, Trillium QuikQuant anti-HbF FITC kit (Trillium Diagnostics, USA), in comparison with the Millipore anti-HbF FITC method. METHODS: Blood from 67 antenatal or postpartum RhD-negative women together with 108 samples spiked with 0.2%, 0.4%, 0.6%, 2%, 4%, 5%, 6%, 8% and 10% of foetal red cells were analysed by both methods. RESULTS: Results for both methods were linear to 10% foetal red cells. Analysis using the Wilcoxon test found that there was no difference between the paired results of Trillium QuikQuant and the expected values of the spiked samples (P = 0.48). In contrast, Millipore anti-HbF FITC gave statistically higher results compared with both the expected values and Trillium QuikQuant anti-HbF FITC (P = 0.0003 and P < 0.0001, respectively). The Bland-Altman plot for Trillium QuikQuant showed a mean difference of only 0.06% below the expected values, whilst Millipore was 0.13% above. The analysis time with Trillium QuikQuant was approximately 40 min, requiring significantly less hands-on time than the Millipore method that required an additional four wash steps. CONCLUSION: Trillium QuikQuant is a new precise, accurate and rapid flow cytometric kit method for the quantitation of FMH in both the antenatal and postpartum period.

Iron studies and red cell transfusion in cardiothoracic and orthopaedic surgical patients: a retrospective audit at a tertiary hospital.

BACKGROUND AND OBJECTIVES: Preoperative diagnosis and treatment of anaemia are important to minimize adverse postoperative outcomes. This audit reviewed red cell transfusion practice, degree of anaemia, iron deficiency anaemia (IDA) and chronic disease or anaemia of inflammation (AI) in cardiothoracic and orthopaedic surgical patients who had available iron studies. MATERIALS AND METHODS: A total of 178 consecutive cardiothoracic and orthopaedic surgical patients with available iron studies were retrospectively reviewed. RESULTS: Of patients, 36·5% had preoperative iron studies. However, 63·2% males and 45·3% females with postoperative iron studies presented with anaemia; 38·5% patients with preoperative iron studies had AI; 21·5% IDA; 23·1% normal. For patients with iron studies requested within the first two postoperative intervals (≤ 5 days and 6 ≤ 10 days) 73·8% and 63·6%, respectively, had AI; few had classical IDA or were normal, and 51·5% patients transfused postsurgery had a discharge Hb ≥ 110 g/l. Restricting the discharge Hb to 90 or 100 g/l may have eliminated postsurgical transfusion in 14·8-42·6% patients. CONCLUSION: Iron studies were more commonly requested postoperatively despite many being anaemic at admission. A higher proportion of patients with postoperative iron studies had AI, and few had classical IDA or normal iron parameters, suggesting a transient inflammatory effect of surgery. This may mask underlying IDA or normal iron parameters and affect treatment. Preadmission assessment, including iron status, should be emphasized allowing diagnosis and correction of presurgical anaemia with treatment modalities other than red cell transfusion. In the postsurgical setting, consideration of a restrictive transfusion regimen sufficient to alleviate a patient's clinical symptoms would ensure that this valuable resource is appropriately used.

Red cell transfusion for iron-deficiency anaemia: a retrospective audit at a tertiary hospital.

BACKGROUND AND OBJECTIVES: The role of red cell transfusion in the management of iron-deficiency anaemia is controversial. This audit was undertaken to monitor the overall transfusion practices of patients admitted to a 600-bed acute tertiary hospital with confirmed severe iron deficiency. MATERIALS AND METHODS: Data from 615 consecutive patients with iron deficiency and no evidence of iron therapy during the period from 1 March 2001 to 30 September 2005 were retrospectively reviewed. RESULTS: Of the 615 iron-deficient patients, 39.2% were transfused. Overall transfused patients were significantly older (mean 73 years old vs. 53 years old; P < 0.0001) with more comorbidities than those not transfused. The pretransfusion haemoglobin (Hb) was < 90 g/l in 92.5% compared to 15.4% of patients not transfused. The post-transfusion Hb was > or = 100 g/l in 75.0% of patients and > or = 110 g/l in 44.2%. Although currently rare (2.5% patients) our speculative data suggest that single red cell transfusions may be appropriate in < or = 29% of patients if restrictive thresholds were adopted. CONCLUSION: Red cell transfusions are commonly administered to elderly patients with severe iron-deficiency anaemia. They may be necessary to alleviate severe morbidity until the time at which iron therapy becomes clinically effective. However, greater emphasis should be given to restrictive transfusion strategies and dosing. Transfusion of single red cell units followed by clinical assessment will determine the need for subsequent units and ensure that this valuable resource is appropriately used.

The utility of an automated electronic system to monitor and audit transfusion practice.

BACKGROUND AND OBJECTIVES: Transfusion laboratories with transfusion committees have a responsibility to monitor transfusion practice and generate improvements in clinical decision-making and red cell usage. However, this can be problematic and expensive because data cannot be readily extracted from most laboratory information systems. To overcome this problem, we developed and introduced a system to electronically extract and collate extensive amounts of data from two laboratory information systems and to link it with ICD10 clinical codes in a new database using standard information technology. MATERIALS AND METHODS: Three data files were generated from two laboratory information systems, ULTRA (version 3.2) and TM, using standard information technology scripts. These were patient pre- and post-transfusion haemoglobin, blood group and antibody screen, and cross match and transfusion data. These data together with ICD10 codes for surgical cases were imported into an MS ACCESS database and linked by means of a unique laboratory number. Queries were then run to extract the relevant information and processed in Microsoft Excel for graphical presentation. We assessed the utility of this data extraction system to audit transfusion practice in a 600-bed adult tertiary hospital over an 18-month period. RESULTS: A total of 52 MB of data were extracted from the two laboratory information systems for the 18-month period and together with 2.0 MB theatre ICD10 data enabled case-specific transfusion information to be generated. The audit evaluated 15,992 blood group and antibody screens, 25,344 cross-matched red cell units and 15,455 transfused red cell units. Data evaluated included cross-matched to transfusion ratios and pre- and post-transfusion haemoglobin levels for a range of clinical diagnoses. Data showed significant differences between clinical units and by ICD10 code. CONCLUSION: This method to electronically extract large amounts of data and linkage with clinical databases has provided a powerful and sustainable tool for monitoring transfusion practice. It has been successfully used to identify areas requiring education, training and clinical guidance and allows for comparison with national haemoglobin-based transfusion guidelines.

The role of RhD agglutination for the detection of weak D red cells by anti-D flow cytometry.

Anti-D flow cytometry is an accurate method for quantifying feto-maternal haemorrhage (FMH). However, weak D red cells with <1000 RhD sites are not detectable using this methodology but are immunogenic. As quantitation of RhD sites is not practical, an alternative approach is required to identify those weak D fetal red cells where anti-D flow cytometry is inappropriate. We describe a simple algorithm based on RhD agglutination and flow cytometry peak separation. All weak D (n = 34) gave weak agglutination with RUM-1 on immediate spin (grading

Case report: immune anti-D stimulated by transfusion of fresh frozen plasma.

FFP has occasionally been reported to generate an immune response to RBC antigens (e.g., anti-D and anti-Fya). The Council of Europe requires that each unit of FFP have less than 6 x 10(9)/L RBCs. However, there is considerable variation internationally in the method of production and the level and assessment of RBC contamination of FFP. This study reports the case of a 63-year-old group B, D- man who received multiple transfusions of D- blood products over a 4-month period. Seven months later the patient's antibody screen remained negative and he was transfused with seven units of D- RBCs and six units of FFP, four of which were D+. Two months later anti-D, -E, and -K were detected in his plasma. Although the anti-E and anti-K could have resulted from transfusion of antigen-positive RBCs, the anti-D could have resulted only from transfusion of the D+ FFP. The D status of FFP is currently not considered when selecting products for transfusion even though the D antigen is highly immunogenic and the level of RBC contamination of FFP is not always known. This case highlights that transfusion of FFP is a stimulus for RBC antibodies and that when a patient has had a recent transfusion of FFP, consideration should be given to obtaining a sample for pretransfusion testing within 3 days before a scheduled RBC transfusion. In addition, the D status of FFP should be considered before administering FFP to premenopausal D- women.

Detection of massive transplacental haemorrhage by flow cytometry.

Flow cytometry has been shown to be a more accurate and sensitive method than the Kleihauer-Betke test for the measurement of feto-maternal haemorrhage in Rh(D) incompatibility. This report describes the successful use of flow cytometry to detect and monitor the management of a massive transplacental haemorrhage (105 ml) of fetal Rh(D) positive cells in a Rh(D) negative woman. The report highlights the accuracy and reproducibility of the test and the stability of a blood sample when transferred 596 kilometres to a central testing facility.