Factors affecting red blood cell storage age at the time of transfusion.

Background: Clinical trials are investigating the potential benefit resulting from a reduced maximum storage interval for red blood cells (RBCs). The key drivers that determine RBC age at the time of issue vary among individual hospitals. Although progressive reduction in the maximum storage period of RBCs would be expected to result in smaller hospital inventories and reduced blood availability, the magnitude of the effect is unknown.

BMI and obesity in US blood donors: a potential public health role for the blood centre.

Objective: According to the 2007-2008 National Health and Nutrition Examination Survey, the prevalence of obesity in the US population was 33·8 %; 34·3 % and 38·2 %, respectively, in middle-aged men and women. We asked whether available blood donor data could be used for obesity surveillance.

Design: Cross-sectional study of BMI and obesity, defined as BMI ≥ 30·0 kg/m2.

The impact of HFE mutations on haemoglobin and iron status in individuals experiencing repeated iron loss through blood donation*.

Frequent blood donors become iron deficient. HFE mutations are present in over 30% of donors. A 24-month study of 888 first time/reactivated donors and 1537 frequent donors measured haemoglobin and iron status to assess how HFE mutations impact the development of iron deficiency erythropoiesis.

Iron deficiency in blood donors: the REDS-II Donor Iron Status Evaluation (RISE) study.

Background: Blood donors are at risk of iron deficiency. We evaluated the effects of blood donation intensity on iron and hemoglobin (Hb) in a prospective study.

Study Design And Methods: Four cohorts of frequent and first-time or reactivated (FT/RA) blood donors (no donation in 2 years), female and male, totaling 2425, were characterized and followed as they donated blood frequently.

Iron deficiency in blood donors: analysis of enrollment data from the REDS-II Donor Iron Status Evaluation (RISE) study.

Background: Regular blood donors are at risk of iron deficiency, but characteristics that predispose to this condition are poorly defined.

Study Design And Methods: A total of 2425 red blood cell donors, either first-time (FT) or reactivated donors (no donations for 2 years) or frequent donors, were recruited for follow-up. At enrollment, ferritin, soluble transferrin receptor (sTfR), and hemoglobin were determined.

Hepatitis C virus prevalence and clearance among US blood donors, 2006-2007: associations with birth cohort, multiple pregnancies, and body mass index.

Background: During the period 1992-1993, the prevalence of hepatitis C virus (HCV) antibodies (anti-HCV) among US blood donors was 0.36%, but contemporary data on the prevalence of antibody to HCV and the prevalence of HCV RNA are lacking.

Methods: We performed a large, cross-sectional study of blood donors at 6 US blood centers during 2006-2007.

Increased all-cause and cancer mortality in HTLV-II infection.

Background: Human T-lymphotropic virus (HTLV)-I and HTLV-II cause chronic human retroviral infections, but few studies have examined the impact of either virus on survival among otherwise healthy individuals. The authors analyzed all-cause and cancer mortality in a prospective cohort of 155 HTLV-I, 387 HTLV-II, and 799 seronegative subjects.

Methods: Vital status was ascertained using death certificates, the US Social Security Death Index or family report, and causes of death were grouped into 9 categories.

Long-term increases in lymphocytes and platelets in human T-lymphotropic virus type II infection.

Human T-lymphotropic viruses types I and II (HTLV-I and HTLV-II) cause chronic infections of T lymphocytes that may lead to leukemia and myelopathy. However, their long-term effects on blood counts and hematopoiesis are poorly understood. We followed 151 HTLV-I-seropositive, 387 HTLV-II-seropositive, and 799 HTLV-seronegative former blood donors from 5 U.

Viability does not necessarily reflect the hematopoietic progenitor cell potency of a cord blood unit: results of an interlaboratory exercise.

Background: Clinical transplant outcome with umbilical cord blood (UCB) as source of hematopoietic progenitor cells (HPCs) is, among other factors, determined by the total number of viable nucleated cells and/or CD34+ cells in the unit. Quantitative and qualitative losses by processing and cryopreservation and by thawing and washing before transfusion may occur, however. Another reason for a discrepancy between the number of cells in the unit released by the cord blood bank and found in the transplant center may be technical differences in cell counting methods between the two sites.

Management of patients refractory to platelet transfusion.

This article discusses the causes and management of platelet refractoriness. Improvements in the quality of platelets and leukoreduction have reduced the morbidity and mortality related to alloimmunization and refractoriness of patients to platelet transfusion. Alloimmunization can be distinguished from other causes of poor post-transfusion platelet increments by the measurement of platelet alloantibodies.

Multiple-laboratory comparison of in vitro assays utilized to characterize hematopoietic cells in cord blood.

Background: Understanding the variability in results obtained by multiple laboratories is important because cord blood units are distributed worldwide for transplantation.

Study Design And Methods: Four exercises were conducted by multiple laboratories to assess assay variability on nucleated cell (NC), mononuclear cell (MNC) by hematology analyzers [HAs], and CD34+ cell (flow cytometry) measurements. Exercise 1 was an intralaboratory exercise in which the reproducibility of cell measurements was determined.

Fetal genotype for specific inherited thrombophilias is not associated with severe preeclampsia.

Objective: Little is known about the association between fetal thrombophilias and severe preeclampsia. The objective of this study was to examine the association between fetal genotype for factor V Leiden, prothrombin, and methylene tetrahydrofolate reductase (MTHFR) mutations and severe preeclampsia.

Methods: Patients with severe preeclampsia or HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome admitted to Georgetown University Hospital were retrospectively identified.

Respiratory and urinary tract infections, arthritis, and asthma associated with HTLV-I and HTLV-II infection.

Human T-lymphotropic virus types I and II (HTLV-I and -II) cause myelopathy; HTLV-I, but not HTLV-II, causes adult T-cell leukemia. Whether HTLV-II is associated with other diseases is unknown. Using survival analysis, we studied medical history data from a prospective cohort of HTLV-I- and HTLV-II-infected and -uninfected blood donors, all HIV seronegative.

Thrombocytopenia in pregnancy.

Thrombocytopenia, classically defined as a platelet count of lower than 150,000/mL, has been observed in 7% to 10% of unselected pregnancies in the past 20 years because platelet counts are included with automated blood cell counters in routine prenatal screenings. Severe thrombocytopenia with a platelet count of lower than 50 x 10(9)/L is rare, occurring in less than 0.1% of pregnancies.

Management of patients refractory to platelet transfusion.

Objective: To present a current assessment and practical approach to the diagnosis and management of patients who are refractory to platelet transfusions.

Design: A task force was convened by the College of American Pathologists under the auspices of the Transfusion Medicine Resource Committee for the purposes of outlining current concepts in the definition and diagnosis of this difficult clinical management problem and selection of the optimal platelet component for these patients.

Results: This article represents a contemporary approach to the diagnosis and management of patients who are refractory to platelet transfusions.