Independent Predictors Of Transfusion Research Articles

The prognostic role of aspartate transaminase to platelet ratio index on outcomes after nonemergent major hepatectomy

IntroductionNoninvasive screening methods to identify patients preoperatively with abnormal liver texture remain limited. Aspartate transaminase to platelet ratio index has been validated to predict fibrosis in patients with hepatitis C; however, its use as a predictor of postoperative outcomes in patients without viral hepatitis remains unknown. MethodsWe queried the American College of Surgeons National Surgical Quality Improvement Program dataset to identify patients who underwent a major hepatectomy between 2014 and 2021. We excluded patients who underwent emergent operations, patients with viral hepatitis, and patients with ascites. Aspartate transaminase to platelet ratio index was calculated using the following equation: (aspartate transaminase/40)/(platelet count) × 100. An aspartate transaminase to platelet ratio index ≥0.7 was used to identify patients with significant fibrosis. Univariable analysis was performed to identify factors associated with aspartate transaminase to platelet ratio index ≥0.7, perioperative transfusion, serious morbidity, overall morbidity, and 30-day mortality. Multivariable logistic regression analysis was performed to identify adjusted predictors of these outcomes. ResultsOf the 8,933 patients who met inclusion criteria, 1,170 (13.1%) patients had an aspartate transaminase to platelet ratio index ≥0.7. A perioperative blood transfusion was administered to 2,497 (28.0%). The number of patients who experienced overall morbidity, serious morbidity, and mortality were 3,195 (35.8%), 2,665 (29.8%), and 238 (2.7%), respectively. Aspartate transaminase to platelet ratio index ≥0.7 was an independent predictor of transfusion (odds ratio: 1.51 [1.32–1.72], P < .001), overall morbidity (1.16 [1.01–1.33], P = .032), and mortality (1.56 [1.12–2.13], P = .006). Transfusion was an independent predictor of overall morbidity (2.50 [2.26–2.76], P < .001), serious morbidity (2.51 [2.26–2.79], P < .001), and mortality (3.28 [2.49–4.33], P < .001). ConclusionAn aspartate transaminase to platelet ratio index ≥0.7 is associated with perioperative transfusion, overall morbidity, and 30-day mortality. The aspartate transaminase to platelet ratio index may serve as a noninvasive tool to risk stratify patients before elective major hepatectomy.

"The Prognostic Role of Aspartate Transaminase to Platelet Ratio Index (APRI) on Outcomes Following Non-emergent Minor Hepatectomy".

Fibrosis and cirrhosis are associated with worse outcomes after hepatectomy. Aspartate transaminase to platelet ratio index (APRI) is associated with fibrosis and cirrhosis in hepatitis C patients. However, APRI has not been studied to predict outcomes after hepatectomy in patients without viral hepatitis. We reviewed the ACS-NSQIP dataset to identify patients who underwent a minor hepatectomy between 2014 and 2021. We excluded patients with viral hepatitis or ascites as well as patients who underwent emergent operations or biliary reconstruction. APRI was calculated using the following equation: (AST/40)/(platelet count) × 100. APRI ≥0.7 was used to identify significant fibrosis. Univariable analysis was performed to identify factors associated with APRI ≥0.7, transfusion, serious morbidity, overall morbidity, and 30-day mortality. Multivariable logistic regression was performed to identify adjusted predictors of these outcomes. Of the 18,069 patients who met inclusion criteria, 1630 (9.0%) patients had an APRI ≥0.7. A perioperative blood transfusion was administered to 2139 (11.8%). Overall morbidity, serious morbidity, and mortality were experienced by 3162 (17.5%), 2475 (13.7%), and 131 (.7%) patients, respectively. APRI ≥0.7 was an independent predictor of transfusion (adjusted OR: 1.48 [1.26-1.74], P < .001), overall morbidity (1.17 [1.02-1.33], P = .022), and mortality (1.97 [1.22-3.06], P = .004). Transfusion was an independent predictor of overall morbidity (3.31 [2.99-3.65], P < .001), serious morbidity (3.70 [3.33-4.11], P < .001), and mortality (5.73 [4.01-8.14], P < .001). APRI ≥0.7 is associated with perioperative transfusion, overall morbidity, and 30-day mortality. APRI may serve as a noninvasive tool to risk stratify patients prior to elective minor hepatectomy.

Incidence, Risk Factors, and Nomogram of Transfusion and Associated Complications in Nonfracture Patients following Total Hip Arthroplasty.

The incidence, risk factors, and associated complications of perioperative transfusion in nonfracture patients following total hip arthroplasty (THA) are unclear. The aim of the present research was to study the predictors of transfusion risk in nonfracture patients following THA and develop a nomogram. One thousand six hundred and thirty-five patients who underwent THA due to nonfracture disease in our institution between September 2013 and July 2017 were included. Independent predictors of transfusion were identified by univariate, LASSO, and multivariate analyses. A nomogram was established based on independent predictors. In addition, a prospective cohort was used to validate the nomogram. The area under the receiver operating characteristic curve was utilized to evaluate the discrimination of the nomogram. Calibration and decision curve analyses were established to evaluate the nomogram. In addition, the association between perioperative transfusion and 30- and 90-day complications was studied. The incidence of transfusion was 15.78%, and 10 independent predictors were confirmed. The areas under the curve of the nomogram were 0.834 and 0.867 in the training and validation cohorts, respectively. Moreover, the area under the curve of the nomogram was significantly higher than that of any single predictor in both the training and validation cohorts. Calibration curve and decision curve analyses in both the training and validation cohorts showed good performance of the nomogram. In addition, perioperative transfusion was identified as an independent risk factor for both 30- and 90-day complications. Generally, ten transfusion-related factors for nonfracture patients following THA were identified. A validated nomogram was established, and several adverse events were confirmed to be associated with transfusion.

Development and validation of a nomogram to predict perioperative blood transfusion in patients undergoing total knee arthroplasty

BackgroundThe need for a transfusion is one of the adverse events following total knee arthroplasty (TKA), and accurately predicting this need remains challenging for arthroplasty surgeons. The purpose of the present research is to study the preoperative predictors of transfusion risk in patients following TKA and develop a nomogram.MethodsThe nomogram was developed based on a training set of 5402 patients who underwent TKA at the Affiliated Hospital of Qingdao University between September 2013 and November 2018. The independent predictors of transfusion were identified by univariate, LASSO, and binary logistic regression analyses. Then, a nomogram was established based on these independent predictors. The area under the curve (AUC), calibration curve, and decision curve analysis (DCA) were selected to evaluate the nomogram. The results were validated using an independent set of 1116 patients who underwent TKA between December 2018 and September 2019. In addition, we also carried out subgroup analyses in the training and testing sets based on the independent predictors.ResultsFive independent predictors were identified by multivariate analysis and were used to establish the nomogram. The AUCs of the nomogram were 0.884 (95% CI: 0.865–0.903) and 0.839 (95% CI, 0.773–0.905) in the training and testing sets, respectively. In both the training and testing sets, the calibration curve indicated that the prediction by the nomogram was highly consistent with the actual observation, and the DCA indicated that the nomogram had a favorable level of clinical usefulness. In addition, the AUC of the nomogram was significantly higher than the AUC of any independent predictor for predicting transfusion risk following TKA, and the subgroup analysis showed good performance in 20 subgroups.ConclusionLower preoperative Hb levels, simultaneous bilateral TKA, lower BMI, older age, and coronary heart disease were identified as independent predictors of postoperative transfusion in patients following TKA. A nomogram incorporating the above five predictors could accurately predict the transfusion risk.

Platelet Activity Measured by VerifyNow® Aspirin Sensitivity Test Identifies Coronary Artery Bypass Surgery Patients at Increased Risk for Postoperative Bleeding and Transfusion

Identifying predictors of bleeding in patients before coronary artery bypass grafting surgery is important, given the complications of bleeding and finite supply of blood. Patient response to aspirin is heterogeneous and can be evaluated using point-of-care platelet function tests. We postulated that patients who hyper-respond to aspirin given preoperatively, as identified by VerifyNow® Aspirin assay (Accumetrics, Inc., San Diego, CA, USA), are at increased risk of bleeding and transfusion. This prospective pilot study examined response to aspirin in patients undergoing coronary artery bypass grafting surgery (n = 61) from 2009 to 2013. Patients with aspirin reaction unit (ARU) values in the lower 50th percentile as identified by VerifyNow® assays were defined as aspirin hyper-responders. The proportion of patients transfused and the median adjusted indexed drop in haemoglobin were compared between aspirin hyper-responders and non-hyper-responders. Logistic regression was performed to determine factors associated with increased risk of transfusion. Seventy per cent (70%) of aspirin hyper-responders were transfused perioperatively compared with 39% of patients who did not hyper-respond, (OR 3.694, 95% CI 1.275-10.706, p = 0.014). VerifyNow® Aspirin hyper-responders had a greater median adjusted indexed drop in haemoglobin compared to non-hyper-responders (34.1 g/L versus 26.6 g/L respectively, p = 0.032). Multivariate analysis also showed VerifyNow® Aspirin hyper-response to be an independent predictor of transfusion (p = 0.016). Other variables such as age, gender, body mass index, renal insufficiency, and cross clamp and bypass times were not predictors of postoperative bleeding in this pilot cohort. VerifyNow® Aspirin is able to preoperatively identify aspirin hyper-responders at an increased risk of bleeding and subsequent transfusion in the context of coronary artery bypass graft surgery.

Adverse Events and Risk Factors of Blood Transfusion in Cardiovascular Surgery: A Prospective Cohort Study

Abstract Background: Hemodilution, transoperative bleeding and cardiopulmonary bypass (CPB) are some of the factors associated with high transfusion rates in cardiac surgery. Objective: To analyze the incidence of blood transfusion and early postoperative outcomes in cardiac surgery patients. Methods: Cohort study of patients undergoing cardiac surgery in a university hospital, consecutively enrolled from May 2015 to February 2017. Data were prospectively collected and comparisons were made between two patients’ groups: transfused and not transfused. Student's t-test, chi-square test, and logistic regression were used, and a p-value < 0.05 was considered significant. Results: Among the 271 patients evaluated, 100 (37%) required transfusion in the transoperative (32.1%) and/or postoperative periods (19.5%). The following predictors of transfusion were identified by multivariate analysis: EuroScore II (OR 1.2); chronic kidney disease (CKD) (OR 3.2); transoperative bleeding ≥ 500 mL (OR 6.7); baseline hemoglobin (Hb) ≤ 10 g/dL (OR 11.5); activated partial thromboplastin time (aPTT) (OR 1.1) and CPB duration (OR 1.03). Transfusion was associated with prolonged mechanical ventilation (≥ 24h) (2.4% vs. 23%), delirium (5.9% vs. 18%), bronchopneumonia (1.2% vs. 16%), acute renal failure (3.5% vs. 25%), acute on CKD (0.6% vs. 8%), stroke or transient ischemic attack (1.8% vs. 8%), intensive care unit stay ≥ 72 h (36% vs. 57%), longer hospital stay (8 ± 4 days vs. 16 ± 15 days), as well as increased early mortality (1.75% vs. 15%). Conclusion: EuroScore II, CKD, major transoperative bleeding, preoperative Hb and aPTT values and CPB time were independent predictors of transfusion, which was associated with a higher rate of adverse outcomes, including early mortality.

Predictive Model for Blood Product Use in Coronary Artery Bypass Grafting.

To build a clinical predictive model to determine the need for transfusing blood and its products in coronary artery bypass grafting (CABG) procedures in South East Asian population. Analytical study. Section of Cardiothoracic Surgery, Aga Khan University Hospital, Karachi, from January 2006 to October 2014. Information on pre-, intra- and postoperative variables were collected for all adult patients who underwent on-pump CABG. The patients grouped into those who received blood and its components, and those who did not. Aunivariate as well as multivariate logistic model was built to determine the predictors of transfusion. A total of 3,550 patients underwent CABG and males were dominant in both groups (75 vs. 93%). The transfusion rate was 56.4% (n=2001). Age (adjusted OR 1.03, p < 0.001), obesity (1.50, p=0.001), tobacco use (1.29, p=0.001), and male gender (4.51, p < 0.001) found to be a stronger predictor. Among preoperative comorbidities, diabetes (1.20, p=0.016), myocardial infarction (1.22, p=0.009), preoperative creatinine (1.12, p=0.033), and left main vessel disease of > 50% (1.49, p < 0.001) were independently associated with the outcome. Compared to elective cases, transfusion rates were high in urgent and emergent cases (OR: 1.93 and 3.36 respectively, p < 0.001 for both). Age, male gender, obesity, tobacco use, diabetes, myocardial infarction, high creatinine, urgent and emergent cases were independent predictors of transfusion in CABG procedure. This model can be utilized for preoperative risk stratification of patients and their management to improve the outcomes.

Endocarditis is not an Independent Predictor of Blood Transfusion in Aortic Valve Replacement Patients With Severe Aortic Regurgitation.

This study sought to evaluate if the presence of endocarditis was independently associated with increased perioperative blood transfusion in patients undergoing aortic valve replacements (AVR) with aortic regurgitation. This was a retrospective study. Large Canadian tertiary care hospital. Six hundred sixty-two consecutive patients with aortic regurgitation score of 3 or higher undergoing AVR from 1995 to 2012. No interventions were performed in this retrospective study. After REB approval, data were obtained from a center-specific database. Univariate analysis was performed to identify variables that may be associated with transfusion of any allogeneic blood product perioperatively. A multivariate logistic regression was generated to identify independent predictors of perioperative transfusion. Unadjusted transfusion rates in patients with no endocarditis and with endocarditis were 32% and 70% (p<0.001), respectively. Independent predictors of any transfusion were moderate-to-severe preoperative anemia, preoperative renal failure, non-isolated AVR, age>70, urgent/emergent surgery, BMI<25, and female sex. Endocarditis was not an independent predictor of transfusion (OR = 0.748; 95% CI = 0.35-1.601). In patients undergoing AVR, unadjusted perioperative transfusion rates were higher when endocarditis was present. However, after adjustment, aortic valve endocarditis was not independently associated with blood transfusion. The authors' observation could be explained by the higher prevalence of many independent predictors of transfusion, such as comorbidities or more complex surgery, within the endocarditis group. Thus, AV endocarditis, in the absence of other risk factors, was not associated with increased perioperative transfusion risk.

Clopidogrel Increases Blood Transfusion and Hemorrhagic Complications in Patients Undergoing Cardiac Surgery

Utilization of the irreversible antiplatelet agent clopidogrel is increasing in the treatment acute coronary syndrome patients. Consequently, more patients are presenting for urgent cardiac surgery with an irreversible defect in platelet function. The objective of this study was to determine whether recent clopidogrel administration predicts transfusion and hemorrhagic complication in cardiac surgery patients. This retrospective study included all patients undergoing isolated coronary artery bypass graft surgery (CABG), isolated valve, or CABG plus valve at a single center between 2004 and 2008. The outcomes of interest were transfusion and hemorrhagic complication. Clopidogrel stop interval was defined as the time between last dose and presentation to the operating room, and was examined in daily increments from 0 to 5 days, more than 5 days, and not receiving clopidogrel preoperatively. By logistic regression, the association of clopidogrel stop interval with transfusion and with hemorrhagic complication was examined after adjusting for other risk factors. Of 3,779 patients included in this study, 26.4% (999) received clopidogrel preoperatively. The overall rates of transfusion and hemorrhagic complication were 34.1% and 4.1%, respectively. Clopidogrel use within 24 hours was an independent predictor of transfusion (odds ratio 2.4; 95% confidence interval: 1.8 to 3.3) and of hemorrhagic complication (odds ratio 2.1; 95% confidence interval: 1.3 to 3.6). Patients receiving clopidogrel within 24 hours of surgery are at increased risk for transfusion and hemorrhagic complication. Timing of surgery for patients receiving clopidogrel should take into account the interval from the last dose.

Plasma fibrinogen level, bleeding, and transfusion after on‐pump coronary artery bypass grafting surgery: a prospective observational study

Early identification of patients with increased risk of excessive bleeding and transfusion after cardiac surgery offers the possibility to initiate countermeasures. Fibrinogen is a key protein in the coagulation cascade and thus a potential biomarker for bleeding. We investigated the relationship between preoperative fibrinogen plasma concentration and postoperative bleeding and transfusion after coronary artery bypass grafting (CABG). A total of 170 patients (mean age, 67 +/- 9 years; 75% men) undergoing isolated CABG were included in a prospective observational study. Patient variables (age, sex, operation time, anticoagulation therapy), preoperative laboratory variables (platelet [PLT] count, activated partial thromboplastin time, prothrombin time, and fibrinogen), postoperative bleeding volume, and transfusions during hospital stay were registered. Independent predictors of bleeding volume and transfusion were identified with multiple regression models. Postoperative bleeding volume correlated univariately with preoperative fibrinogen concentration (r = -0.53, p < 0.001) and PLT count (r = -0.26, p = 0.001) but only preoperative fibrinogen concentration was an independent predictor of postoperative bleeding volume. Twenty-nine of the 170 patients (17%) received transfusions with blood products. Independent predictors of transfusion were preoperative fibrinogen concentration (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1-3.7 per 1-unit decrease; p = 0.027), female sex (OR, 5.0; 95% CI, 1.8-14.7; p = 0.002), and aortic cross-clamp time (OR, 1.03; 95% CI, 1.01-1.06 per minute; p = 0.013). The results indicate that preoperative fibrinogen concentration (even within the normal range) is a limiting factor for postoperative hemostasis. Preoperative measurement of fibrinogen concentration provides information about bleeding volume and transfusion requirements after CABG.

Impact of blood transfusions on outcome after pneumonectomy for thoracic malignancies

The aim of the present study was to determine the risk factors and impact on outcome of blood transfusions following pneumonectomy for thoracic malignancies. A retrospective analysis of 432 consecutive patients was carried out, of whom 183 (42.4%) were transfused post-operatively. The associations between blood transfusions and 20 variables were assessed by univariate and multivariate analysis. Survival analysis included log-rank test and Cox regression model. Patient age, neoadjuvant treatment, completion pneumonectomy and extended procedures were independent predictors of transfusion. It was found that 30-day mortality increased significantly from 2.4% (no transfusion) to 10.9 and 21.9% (<or=2 and >2 red blood cell packs, respectively). Blood transfusion was the strongest predictor of 30-day mortality (odds ratio (OR) 10; 95% confidence interval (CI): 3.7-27), respiratory failure (OR 19.2; 95% CI 7.4-49.4) and infectious complications (OR 3; 95% CI 1.5-6.2). In the 367 lung cancer patients, a significantly lower 5-yr survival was observed in univariate analysis of transfused patients (27.8+/-5.4% versus 39.4+/-4.5%). In a Cox regression analysis, blood transfusion was no longer found to be significant. A dose-related correlation is suggested between blood transfusion and early mortality through an increase of infectious and respiratory complications. In contrast, blood transfusion had no independent adverse impact on long-term survival.

Off-pump coronary artery bypass grafting provides complete revascularization with reduced myocardial injury, transfusion requirements, and length of stay: A prospective randomized comparison of two hundred unselected patients undergoing off-pump versus conventional coronary artery bypass grafting

Objective: Retrospective comparisons of selected patients undergoing off-pump versus conventional on-pump coronary artery bypass grafting have yielded inconsistent results and raised concerns about completeness of revascularization in off-pump coronary artery bypass grafting. Methods: Two hundred unselected patients referred for elective primary coronary artery bypass grafting were randomly assigned to undergo off-pump coronary artery bypass grafting with an Octopus tissue stabilizer (Medtronic, Inc, Minneapolis, Minn) or conventional coronary artery bypass grafting with cardiopulmonary bypass by a single surgeon. Revascularization intent determined before random assignment was compared with the revascularization performed. All management followed strict, unbiased, criteria-driven protocols. Patients and nonoperative care providers were blinded to surgical group. Results: Baseline characteristics were similar. The number of grafts performed per patient (mean ± SD 3.39 ± 1.04 for off-pump coronary artery bypass grafting, 3.40 ± 1.08 for conventional coronary artery bypass grafting) and the index of completeness of revascularization (number of grafts performed/number of grafts intended, 1.00 ± 0.18 for off-pump coronary artery bypass grafting, 1.01 ± 0.09 for conventional coronary artery bypass grafting) were similar. Likewise, the index of completeness of revascularization was similar between groups for the lateral wall. Combined hospital and 30-day mortalities and stroke rates were similar. Postoperative myocardial serum enzyme measures were significantly lower after off-pump coronary artery bypass grafting, suggesting less myocardial injury. Adjusted postoperative thromboelastogram indices, fibrinogen, international normalized ratio, and platelet levels all showed significantly less coagulopathy after off-pump coronary artery bypass grafting. Patients undergoing off-pump coronary artery bypass grafting received fewer units of blood, were more likely to avoid transfusion altogether, and had a higher hematocrit at discharge. Cardiopulmonary bypass was an independent predictor of transfusion (odds ratio 2.42, P =.0073) by multivariate analysis. More patients undergoing off-pump coronary artery bypass grafting were extubated in the operating room and within 4 hours. Postoperative length of stay (in days) was shorter for off-pump coronary artery bypass grafting (5.1 ± 6.5 for off-pump coronary artery bypass grafting, 6.1 ± 8.2 for conventional coronary artery bypass grafting, P =.005 by Wilcoxon test). One patient (in the conventional coronary artery bypass grafting group) required angioplasty for graft closure within 30 days. Conclusions: When compared with conventional coronary artery bypass grafting with cardiopulmonary bypass, off-pump coronary artery bypass grafting achieved similar completeness of revascularization, similar in-hospital and 30-day outcomes, shorter length of stay, reduced transfusion requirement, and less myocardial injury.J Thorac Cardiovasc Surg 2003;125:797-808

Factores predictivos de la necesidad de transfusión en la fractura subcapital de cadera en pacientes mayores de 65 años

Our goal was to know the patient's clinical and hematologic characteristics that could influence the use of blood in subcapital hip fracture (SCHF). A prospective study of all patients affected by SCHF having surgery during 1998. Patients younger than 65 years, with primary blood diseases or under anticoagulation therapy were excluded. Age, gender, elapsed time, type of SCHF (international AO classification), surgical procedure (nail vs. hip arthroplasty), transfusional procedure and total used; hemoglobin (Hb) and hematocrit (Hct) levels at days 0 and + 2 (if surgical procedure was not performed) and after surgery were studied. Also we analyzed different hematimetric parameters: VCM, HCM, and RDW, transfusional act and blood consume. Statistical univariant analysis included T-Student test for numeric variables and Pearson X2 test for string variables. Statistical significance differences were considered when p < 0.05. A multivariate stepwise logistic regression model was carried out. 75 patients with SCHF were studied: 18 B1, 8 B2 and 49 B3 according to AO classification. Male/female: 12/63; age 81(SD: 8) years (range 65-99). At the admission day, the Hb level was 128 (SD: 23) g/L; Hct 0.39 L/L (SD: 0.06) (range 13-52), HCM 30.3 pg, VCM 91.4 fL and RDW 14.3%. The elapsed time was 5 (SD: 2.8) days. 22 patients (29.3%) had anemia on admission. Surgery consisted of: nails in 23 (31%) and hip arthroplasty in 52 (69%) patients. At day + 2 (n: 36) Hb was 119 g/L (SD: 12) and Hct 0.36 L/L (SD: 0.04). 34 (45%) patients were not transfused. On the statitiscal univariant study, Hb and Hct levels at admission and after surgery, RDW (anisocytosis), type of fracture and the surgical act were all associated with a transfusional procedure. In the transfused patients the Hb level (119.9 g/L) was lower than in non-transfused ones (138 g/L) (p < 0.01). 71% hip arthroplasty patients were transfused vs 17% nail patients (p < 0.01). On the logistic regression only the preoperative Hb level (p < 0.01) was identified as an independent predictor of transfusion. These results invite us to improve the hematological parameters in this elderly population and to promote earlier and less aggressive surgical procedures (nails) and to promote the use of alternatives methods to reduce the use of allogenic blood.

A reduction in Type and Screen: preoperative prediction of RBC transfusions in surgery procedures with intermediate transfusion risks †

In many patients, a 'type and screen' procedure is routinely performed before surgery. However, most patients are not transfused after all. Can we predict, which surgical patients will and will not be transfused, to reduce the number of these investigations? We studied 1482 consecutive surgical patients with intermediate risk for transfusion. Multivariate logistic regression modelling and the area under the Receiver Operating Characteristic curve (ROC area) were used to quantify how well age, gender, surgical procedure, emergency or elective surgery and anaesthetic technique predicted transfusion, and whether the preoperative haemoglobin concentration had added predictive value. Gender, age > or =70 yr, and type of surgery were independent predictors of transfusion, with a ROC area of 0.75 (95% CI: 0.72-0.79). Validating this model with an easily used prediction rule in a second patient population yielded a ROC area of 0.70 (95% CI: 0.63-0.77). With this rule type and screen could correctly be withheld in 35% of these patients. In the remaining 65% of the patients, a further reduction in type and screen investigations of 15% could be achieved using the preoperative haemoglobin concentration. Using a simple prediction rule, preoperative type and screen investigations in patients who have to undergo surgery procedures with intermediate transfusion risk can be avoided in about 50%. This may reduce patient burden and hospital costs (on average: 3 million US$ per 100 000 procedures).