Detection of Babesia RNA and DNA in whole blood samples from US blood donations.

BACKGROUND: Human babesiosis is a zoonotic infection caused by an intraerythrocytic parasite. The highest incidence of babesiosis is in the United States, although cases have been reported in other parts of the world. Due to concerns of transfusion-transmitted babesiosis, the US Food and Drug Administration (FDA) recommended year-round regional testing for Babesia by nucleic acid testing or use of an FDA-approved device for pathogen reduction. A new molecular test, cobas Babesia (Roche Molecular Systems, Inc.), was evaluated for the detection of the four species that cause human disease, Babesia microti, Babesia duncani, Babesia divergens, and Babesia venatorum. STUDY DESIGN AND METHODS: Analytical performance was evaluated followed by clinical studies on whole blood samples from US blood donations collected in a special tube containing a chaotropic reagent that lyses the red cells and preserves nucleic acid. Sensitivity and specificity of the test in individual samples (individual donation testing [IDT]) and in pools of six donations were determined. RESULTS: Based on analytical studies, the claimed limit of detection of cobas Babesia for B. microti is 6.1 infected red blood cells (iRBC)/mL (95% confidence interval [CI]: 5.0, 7.9); B. duncani was 50.2 iRBC/mL (95% CI: 44.2, 58.8); B. divergens was 26.1 (95% CI: 22.3, 31.8); and B. venatorum was 40.0 iRBC/mL (95% CI: 34.1, 48.7). The clinical specificity for IDT was 99.999% (95% CI: 99.996, 100) and 100% (95% CI: 99.987, 100) for pools of six donations. CONCLUSION: cobas Babesia enables donor screening for Babesia species with high sensitivity and specificity.

Sensitivity and specificity of a new automated system for the detection of hepatitis B virus, hepatitis C virus, and human immunodeficiency virus nucleic acid in blood and plasma donations.

BACKGROUND: Use of nucleic acid testing (NAT) in donor infectious disease screening improves transfusion safety. Advances in NAT technology include improvements in assay sensitivity and system automation, and real-time viral target discrimination in multiplex assays. This article describes the sensitivity and specificity of cobas MPX, a multiplex assay for detection of human immunodeficiency virus (HIV)-1 Group M, HIV-2 and HIV-1 Group O RNA, HCV RNA, and HBV DNA, for use on the cobas 6800/8800 Systems. STUDY DESIGN AND METHODS: The specificity of cobas MPX was evaluated in samples from donors of blood and source plasma in the United States. Analytic sensitivity was determined with reference standards. Infectious window periods (WPs) before NAT detectability were calculated for current donor screening assays. RESULTS: The specificity of cobas MPX was 99.946% (99.883%-99.980%) in 11,203 blood donor samples tested individually (IDT), 100% (99.994%-100%) in 63,012 donor samples tested in pools of 6, and 99.994% (99.988%-99.998%) in 108,306 source plasma donations tested in pools of 96. Seven HCV NAT-yield donations and one seronegative occult HBV infection were detected. Ninety-five percent and 50% detection limits in plasma (IU/mL) were 25.7 and 3.8 for HIV-1M, 7.0 and 1.3 for HCV, and 1.4 and 0.3 for HBV. The HBV WP was 1 to 4 days shorter than other donor screening assays by IDT. CONCLUSION: cobas MPX demonstrated high specificity in blood and source plasma donations tested individually and in pools. High sensitivity, in particular for HBV, shortens the WP and may enhance detection of occult HBV.

First Zika-positive donations in the continental United States.

BACKGROUND: Zika virus (ZIKV) has spread in the Americas, including parts of the southern United States, and infection can be associated with serious complications, including congenital brain abnormalities. Probable transfusion transmission of ZIKV has been documented in Brazil. STUDY DESIGN AND METHODS: Preemptive testing of blood donations for ZIKV RNA was implemented in southern US states at risk of local transmission using a test approved under a Food and Drug Administration (FDA) investigational new drug application, cobas Zika. Screening was expanded after issuance of an updated FDA guidance. Donations reactive on initial screening were further tested by nucleic acid and antibody tests to determine the donor status. RESULTS: Of 358,786 donations from US states screened by individual donation testing, 23 were initially reactive on cobas Zika. Fourteen of these represented probable ZIKV infection based on reactivity on additional nucleic acid testing or anti-Zika immunoglobulin M. Ten of the 14 donors reported travel to an identified ZIKV-active area within 90 days before donation (median time from end of travel to donation, 25 days; range, 6-71 days). Three donors with travel history also had a potential sexual exposure. Only seven of the 14 donations with probable ZIKV infection were detectable upon 1:6 dilution to simulate minipool testing. The estimated specificity of the cobas Zika test was 99.997%. CONCLUSION: Screening of donations for ZIKV RNA can interdict ZIKV-infected donors. Donor risk factors include travel more than 4 weeks before donation and sexual exposure. Minipool screening would have detected only 50% of the RNA-positive donations.

Anti-Ge3 causes late-onset hemolytic disease of the newborn: the fourth case in three Hispanic families.

BACKGROUND: The Gerbich (Ge) blood group system consists of 11 antigens carried on red blood cell (RBC) membrane glycophorins C and D; of these, Ge:3 antigen is of high prevalence, and the anti-Ge3 is found to be clinically significant. CASE REPORT: A 34-week neonate born to a Hispanic mother with anti-Ge3 developed late-onset hemolysis with hyperbilirubinemia and was successfully treated with transfusions from her mother. Relevant clinical findings and laboratory results for this case are summarized and compared to three other previously reported cases; all babies were born from a mother of Hispanic ethnicity. CONCLUSION: Hemolytic disease of the fetus and new born associated with anti-Ge3 is rare but should be considered when working up a broadly reactive RBC antibody screen in women of Hispanic ethnicity. Early identification of pregnant women with anti-Ge3 is recommended for prenatal transfusion planning and close monitoring of the newborn infant for evidence of late-onset anemia.