Blood donor deferral in Minas Gerais State, Brazil: blood centers as sentinels of urban population health.

BACKGROUND: Shortage of safe blood donors is frequent and it is important to understand the causes of deferral of potential donors, who reside mainly in urban areas, to improve recruitment campaigns aiming at the quality/availability of donors. STUDY DESIGN AND METHODS: In Minas Gerais State, Brazil, Hemominas Foundation collects, analyzes, and distributes more than 90 percent of blood. Blood is collected in 19 centers in cities. In 2006, data from 335,109 attempts to donate were analyzed. RESULTS: Seventy-seven percent of donor candidates were less than 40 years old, with 57.1 percent nonwhite and 66 percent male. A total of 21.6 percent were deferred at the interview. Women were more clinically deferred than men (25.5% vs. 19.6%). In larger cities, the proportion of first-time donors (FTs) was higher (67.8%). The main causes of permanent deferral among FTs were neurologic diseases (37.5%), chronic hypertension (22.2%), and endocrinologic diseases (9.9%). The main causes of temporary clinical deferral in this group were risky behavior for sexually transmitted diseases (32.6%), anemia (8.5%), and hypertension (6%). The main causes of permanent deferral in repeat donors (RTs) were chronic hypertension (31.6%) and neurologic diseases (22.1%); for temporary deferral it was anemia (22.6%). A total of 2.9% of the collected blood bags were discarded due to reactive tests (FTs = 34.82/1000; RTs = 3.51/1000). CONCLUSION: A deferral study in blood donor candidates may shed light on regional diversity, highlighting how social inequalities and health status of the general population may affect the blood supply. Risk factors and marker rates derived from the donor pool may be useful to gain insights regarding public health issues.

Managing suspected venous thromboembolism in a mixed primary and secondary care setting using standard clinical assessment and D-dimer in a noninvasive diagnostic strategy.

Venous thromboembolism is a potentially lethal disease if not properly treated. Noninvasive strategies have become an attractive clinical option for effective diagnosis. There has been controversy, however, regarding the use of standard clinical rules in a primary care setting. The objective of the present study was to validate a noninvasive diagnostic strategy in an emergency unit giving assistance to patients with primary and secondary care needs. A total of 291 outpatients (primary and secondary care needs) with suspected venous thromboembolism attending the emergency unit of a general hospital from August 2002 to 2004 were retrospectively evaluated. The diagnostic strategy included assessment of risk for venous thromboembolism and a rapid quantitative enzyme-linked immunosorbent assay D-dimer test. Venous thromboembolism was ruled out in patients with a low-probability or intermediate-probability risk (or an unlikely diagnosis) and a negative D-dimer. The prevalence of venous thromboembolism was 8.2%. Patients with an unlikely diagnosis comprised 93.8% of the evaluations for deep venous thrombosis, and those with a low probability for pulmonary embolism comprised 81.4%. Proportions of patients with venous thromboembolic events observed were 7.2% in patients with an unlikely diagnosis of deep venous thrombosis and 3.0% in those with low probability for pulmonary embolism. The percentage of patients with a thrombotic event excluded using this strategy was 37% (positive predictive value 13%, negative predictive value 100%). In conclusion, this noninvasive clinical strategy is safe for ruling out venous thromboembolism, and excludes the need for imaging tests in about one-third of the patients in the population studied.