Glycated hemoglobin measurements from dried blood spots: Reliability and relation to results obtained from whole blood samples

Background: Main objective was to measure glycated hemoglobin (HbA1c) in dried blood spots on paper filter and in whole blood samples in diabetic patients to evaluate relationship between two methods and their respective reliability. Methods: The 20�10 μl of venous blood samples of 33 diabetics were blotted onto the filter paper allowed to dry at room temperature and then stored at 25°C and 4°C. HbA1c was measured via the Turbidimetric Inhibition Immunoassay Technique. The relation was evaluated with correlation and linear regression tests using STATA software and SPSS. Agreement between the results obtained from the dried blood spots and others was evaluated using the Bland and Altman. The pitman's permutation test was also employed to compare the difference in variance. Results: A high positive correlation was detected between whole blood samples and dried blood spots stored at 4°C (r2 =0.90) and at 25°C (r2 = 0.95). The Bland and Altman graphs, as well as the Pitman tests, showed statistically significant differences in variability between the values obtained from whole blood samples and those derived from dried spots stored at 4°C (p=0.05) or 25°C (p=0.004). Conclusion: HbA1c measurements from dried blood spots on the filter paper yielded reliable results. That the Hitachi autoanalyzer is available in most countries renders this assay less costly than the High Performance Liquid Chromatography Method (HPLC). In addition, the filter paper method for Immuno-turbidimetric estimations of HbA1c at different temperatures is reliable and may be particularly useful in outpatient diabetes clinic

Reader Expectation and the Ethnic Rhetorics: The Problem of the Passing Subaltern in Who Would Have Thought It?

Mrs. Norval... hoped...Lola might be now all black or all white, no matter which, only not with those ugly white spots. - Who Would Have Thought It? 1872 (78) But these snowy, equable and smooth spots ... sometimes occur amongst our own people. I have myself had the opportunity of observing two instances of this kind .. .The skin of each was brownish, studded here and there with very white spots of different sizes. - Mulattos The Anthropological Treatises of Johann Friedrich Blumenbach, 1865 (220) As illustrated by these two excerpts, the mixed blood provoked in Johann Friedrich Blumenbach, as it does in Marfa Amparo Ruiz de Burton\u27s Mrs. Norval, a kind of tension, a sometimes explicit, often insidious fear of racial unreadability and its implications for white domination

Combined DNA extraction and antibody elution from filter papers for the assessment of malaria transmission intensity in epidemiological studies.

BACKGROUND: Informing and evaluating malaria control efforts relies on knowledge of local transmission dynamics. Serological and molecular tools have demonstrated great sensitivity to quantify transmission intensity in low endemic settings where the sensitivity of traditional methods is limited. Filter paper blood spots are commonly used a source of both DNA and antibodies. To enhance the operational practicability of malaria surveys, a method is presented for combined DNA extraction and antibody elution. METHODS: Filter paper blood spots were collected as part of a large cross-sectional survey in the Kenyan highlands. DNA was extracted using a saponin/chelex method. The eluate of the first wash during the DNA extraction process was used for antibody detection and compared with previously validated antibody elution procedures. Antibody elution efficiency was assessed by total IgG ELISA for malaria antigens apical membrane antigen-1 (AMA-1) and merozoite-surface protein-1 (MSP-142). The sensitivity of nested 18S rRNA and cytochrome b PCR assays and the impact of doubling filter paper material for PCR sensitivity were determined. The distribution of cell material and antibodies throughout filter paper blood spots were examined using luminescent and fluorescent reporter assays. RESULTS: Antibody levels measured after the combined antibody/DNA extraction technique were strongly correlated to those measured after standard antibody elution (p < 0.0001). Antibody levels for both AMA-1 and MSP-142 were generally slightly lower (11.3-21.4%) but age-seroprevalence patterns were indistinguishable. The proportion of parasite positive samples ranged from 12.9% to 19.2% in the different PCR assays. Despite strong agreement between outcomes of different PCR assays, none of the assays detected all parasite-positive individuals. For all assays doubling filter paper material for DNA extraction increased sensitivity. The concentration of cell and antibody material was not homogenously distributed throughout blood spots. CONCLUSION: Combined DNA extraction and antibody elution is an operationally attractive approach for high throughput assessment of cumulative malaria exposure and current infection prevalence in endemic settings. Estimates of antibody prevalence are unaffected by the combined extraction and elution procedure. The choice of target gene and the amount and source of filter paper material for DNA extraction can have a marked impact on PCR sensitivity

Detection of HIV-1 infection in dried blood spots from a 12-year-old ABO bedside test card

Background and Objectives: We tested dried blood from an ABO bedside test card which had been stored at room temperature for 12 years, to prove that a patient with HIV-1 infection had been infected by blood transfusion. Materials and Methods: Immunoblots for HIV-1 antibodies and threefold PCRs with half-nested primers for the HIV-1 integrase gene were done with eluates from the dried blood spots. Results: HIV-1 antibodies and HIV-1 DNA could be detected in the sample from one unit of blood, but not from the two other units or from the recipient before transfusion. Conclusion: Further studies should be done on the validity of stored dried blood as an alternative to the storage of frozen donor serum for several years for `look-back' studies

Canine Trypanosoma cruzi infection in the Bolivian Chaco

A cross-sectional study on Trypanosoma cruzi was carried out in 2013 to evaluate the role of dogs as possible source of infection for humans in two rural communities of the highly endemic Bolivian Chaco (Bartolo, Chuquisaca Department, n = 57 dogs; and Ivamirapinta, Santa Cruz Department, n = 48 dogs). Giemsa-stained thick and thin smears, rapid immunochromatographic test (ICT) (Chagas Quick test, Cypress Diagnostic, Belgium) and polymerase chain reaction for T. cruzi on dried blood spots were performed. All smears proved negative by microscopic examination, whereas 23/103 (22%) were positive by ICT and 5/105 (5%) blood samples contained T. cruzi DNA, evidencing the potential role of dogs in the domestic transmission of the parasite

Role of therapeutic drug monitoring in pulmonary infections : use and potential for expanded use of dried blood spot samples

Respiratory tract infections are among the most common infections in men. We reviewed literature to document their pharmacological treatments, and the extent to which therapeutic drug monitoring (TDM) is needed during treatment. We subsequently examined potential use of dried blood spots as sample procedure for TDM. TDM was found to be an important component of clinical care for many (but not all) pulmonary infections. For gentamicin, linezolid, voriconazole and posaconazole dried blood spot methods and their use in TDM were already evident in literature. For glycopeptides, beta-lactam antibiotics and fluoroquinolones it was determined that development of a dried blood spot (DBS) method could be useful. This review identifies specific antibiotics for which development of DBS methods could support the optimization of treatment of pulmonary infections

Early changes in pro-inflammatory cytokine levels in neonates with encephalopathy are associated with remote epilepsy.

BackgroundNeonatal seizures are associated with adverse neurologic sequelae including epilepsy in childhood. Here we aim to determine whether levels of cytokines in neonates with brain injury are associated with acute symptomatic seizures or remote epilepsy.MethodsThis is a cohort study of term newborns with encephalopathy at UCSF between 10/1993 and 1/2000 who had dried blood spots. Maternal, perinatal/postnatal, neuroimaging, and epilepsy variables were abstracted by chart review. Logistic regression was used to compare levels of cytokines with acute seizures and the development of epilepsy.ResultsIn a cohort of 26 newborns with neonatal encephalopathy at risk for hypoxic ischemic encephalopathy with blood spots for analysis, diffuse alterations in both pro- and anti-inflammatory cytokine levels were observed between those with (11/28, 39%) and without acute symptomatic seizures. Seventeen of the 26 (63%) patients had &gt;2 years of follow-up and 4/17 (24%) developed epilepsy. Higher levels of pro-inflammatory cytokines IL-6 and TNF-α within the IL-1β pathway were significantly associated with epilepsy.ConclusionsElevations in pro-inflammatory cytokines in the IL-1β pathway were associated with later onset of epilepsy. Larger cohort studies are needed to confirm the predictive value of these circulating biomarkers

Newborn screening using tandem mass spectrometry: A systematic review

Objectives: To evaluate the evidence for the clinical effectiveness of neonatal screening for phenylketonuria (PKU) and medium-chain acyl-coA dehydrogenase (MCAD) deficiency using tandem mass spectrometry (tandem MS). Study design: Systematic review of published research. Data sources: Studies were identified by searching 12 electronic bibliographic databases; conference proceedings and experts consulted. Results: Six studies were selected for inclusion in the review. The evidence of neonatal screening for PKU and MCAD deficiency using tandem MS was primarily from observational data of large-scale prospective newborn screening programmes and systematic screening studies from Australia, Germany and the USA. Tandem MS based newborn screening of dried blood spots for PKU and/or MCAD deficiency was shown to be highly sensitive (>93.220%) and highly specific (>99.971%). The false positive rate for PKU screening was less than 0.046% and for MCAD deficiency the false positive rate was less than 0.023%. The positive predictive values ranged from 20 to 32% and 19 to 100%, respectively. Conclusions: This review suggests that neonatal screening of dried blood spots using a single analytical technique (tandem MS) is highly sensitive and specific for detecting cases of PKU and MCAD deficiency, and provides a basis for modelling of the clinical benefits and potential costeffectiveness

A note on the use of FTA™ technology for storage of blood samples for DNA analysis and removal of PCR inhibitors

peer-reviewedFTA™ technology is widely used across many molecular disciplines for sample capture, storage and analysis. The use of this technology for the long-term storage of blood samples for DNA analysis was examined as well as its potential to remove inhibitors from DNA samples previously extracted from blood with PCR inhibitors remaining. It was found that blood spots stored on FTA™ cards for 8 years at room temperature gave successful PCR products and that FTA™ cards are a useful tool for removing substances in samples which interfere with or inhibit, the PCR reaction