This study provides data on National Blood Service (NBS) red blood cell (RBC, n = 9142), platelet (PLT, n = 4232) and fresh frozen plasma (FFP, n = 3584) recipients independently sampled by monthly quota from 29 representative hospitals over 12 months in 2001-2002. Hospitals were stratified by size according to total yearly RBC issues. Transfusion indications were chosen from diagnostic and procedural codes, and recipients grouped into Epidemiology and Survival of Transfusion Recipients Case-mix Groups (E-CMGs). The main E-CMGs were digestive [19% of RBC recipients; including 5% gastrointestinal (GI) bleeds and 3% colorectal surgery], musculoskeletal (15%; 12% hip and knee replacement), haematology (13%) and obstetrics and gynaecology (10%). Renal failure, fractured neck of femur, cardiac artery by-pass grafting (CABG) and paediatrics, each accounted for 3-4% recipients. FFP recipients: the main E-CMGs were digestive (21% of FFP recipients; including 7% GI bleeds and 3% colorectal surgery), hepatobiliary (15%; 7% liver disease and 2% liver transplant), cardiac (12%) and paediatrics (9%) The renal, paediatrics, vascular and haematology E-CMGs each had 6-7% of recipients. PLT recipients: the main E-CMGs were haematology (27% of PLT recipients; including 9% lymphoma and 8% acute leukaemia), cardiac (17%), paediatrics (13%), hepatobiliary (10%) and digestive (9%). Back-weighting gave national estimates of 433 000 RBC, 57 500 FFP and 41 500 PLT recipients/year in England and North Wales, median age 69, 64 and 59 years, respectively. Digestive and hepatobiliary indications emerged as the top reason for transfusion in RBC and FFP recipients, and was also a frequent indication in PLT recipients.

Previous studies of blood use have used different methods to obtain and classify transfusion indications. Before undertaking a national study of transfusion recipients, a pilot study was performed over 2 months at two teaching and two district general hospitals to match information from hospital transfusion laboratories with clinical coding data from the hospital's Patients Administration System to determine the indication for transfusion in 2468 recipients. Data analysis revealed major limitations in the conventional use of primary diagnostic International Statistical Classification of Disease and Related Health Problems 10th Revision (ICD-10) or procedure Office of Population, Censuses and Surveys - Classification of Surgical Operations and Procedures - 4th Revision (OPCS-4) codes alone in allocating transfusion indications. A novel algorithm was developed, using both types of code, to select the probable indication for transfusion for each patient. A primary OPCS-4 code was selected for recipients transfused in relation to surgery (43%) and either the primary (36%) or the secondary (12%) ICD-10 code was chosen for recipients transfused for medical reasons. The remaining patients were unclassified. Selected codes were then collated into Epidemiology and Survival of Transfusion Recipients (EASTR) casemix groups (E-CMGs). The most frequent E-CMGs were haematology (15% of recipients), musculoskeletal (14%), digestive system (12%) and cardiac (10%). The haematology E-CMG includes patients with malignant and non-malignant blood disorders and recipients transfused for anaemia where no cause was listed. Recipients undergoing hip and knee replacement and coronary artery bypass grafting are within the musculoskeletal and cardiac E-CMGs. The digestive E-CMG includes recipients transfused for gastrointestinal (GI) bleeds and those undergoing GI surgery. This methodology provides a more useful means of establishing the probable indication for transfusion and arranging recipients into clinically relevant groups.