Clinical laboratory science : journal of the American Society for Medical Technology最新文献

The objective of this study was to develop a simple, cost-effective method of HbF determination potentially useable in underdeveloped countries to determine sickle cell patient response to hydroxyurea treatment. Normal adult blood (HbA), cord blood (HbF), and a 50:50 mixture (HbA+F) were the three sample types used in procedure development. Normal blood samples were collected from the research team, and de-identified cord blood samples were provided by Cardinal Glennon Pediatric Research Institute, St. Louis, MO. The hematocrit of all blood samples was standardized to 35%. The method, based on the Kleihauer-Betke (K-B) test principle, used a citrate solution to selectively elute HbA from RBCs while HbF remained intracellular, and spectrophotometric absorbance of the eluate was the primary outcome measure. A procedure was developed and optimized utilizing a 395 nm wavelength, 30 sec centrifugation time, 6 min incubation time, 20 microL blood volume, and 0.07 M sodium citrate in a 0.06 M sodium phosphate buffer solution. Reproducibility was demonstrated (N = 39) with a mean HbA absorbance of 1.285 (SD 0.069), mean HbA+F absorbance of 0.690 (SD 0.050), and mean HbF absorbance of 0.035 (SD 0.005), also exhibiting linearity (r2 = 0.99). This simple, cost-effective method of HbF determination shows potential as a basis for determining sickle cell patient response to hydroxyurea treatment in underdeveloped countries.

Objective: To evaluate and characterize MRSA and staphylococci carriage and conversion rates in nursing students across clinical semester rotations and to describe risk factors.

Design: A prospective, longitudinal cohort design (interim report) with three times of measurement. Data collected between August 2010 and May 2011 (ongoing longitudinal study to May 2012). Institutional Review Board approval (2010F5693).

Setting: Texas State University, San Marcos, TX.

Participants: Eighty-seven nursing students.

Interventions: A positive MRSA swab represented an end-point for a participant. Intervention offered was bactroban (mupirocin) for nasal decolonization and an oral antibiotic, doxycycline; posttreatment collection to verify decolonization prior to next clinical rotation.

Main outcome measures: Screening for Staphylococcus aureus and MRSA identification; confirmation and antibiotic susceptibility by Vitek 2. Self-administered questionnaires collected demographics and risk factors. Generalized estimating equations calculated population-averaged panel logistic regression models allowing for an AR(1) error by Stata version 12.

Results: MRSA colonization did not increase. S. aureus prevalence (20-26%). Species prevalence other than S. aureus increased (9.2% to 80%). The following associations were found to be statistically significant: boil or skin infection odds with S. aureus (OR = 2.43, p < .05), working or volunteering in healthcare facility odds with S. other (OR = 2.72, p < .05) and gym and sports activities odds with S. other (OR = 4.98, p < .001).

Conclusions: MRSA colonization did not increase. Knowledge and understanding of MRSA (risks) may play a role in compliance and barrier precautions. S. aureus colonization remained stable (25-30%). Species colonization other than S. aureus (e.g. S. epidermis, S. haemolyticus) increased to significant levels.

In this study, we evaluated the efficacy of virtual microscopy as the primary mode of laboratory instruction in undergraduate level clinical hematology teaching. Distance education (DE) has become a popular option for expanding education and optimizing expenses but continues to be controversial. The challenge of delivering an equitable curriculum to distant locations along with the need to preserve our slide collection directed our effort to digitize the slide sets used in our teaching laboratories. Students enrolled at two performance sites were randomly assigned to either traditional microscopy (TM) or virtual microscopy (VM) instruction. The VM group performed significantly better than the TM group. We anticipate that this approach will play a central role in the distributed delivery of hematology through distance education as new programs are initiated to address workforce shortage needs.

The objective of this study was to develop a diagnostic testing method to detect HbS, distinguish sickle cell homozygotes from heterozygotes, and overcome testing barriers encountered in laboratories in underdeveloped countries. Blood samples positive and negative for sickle cell were subjected to the standard hemoglobin solubility test followed by a variety of centrifugation and filtration procedures. Each procedure was evaluated for the ability to remove insoluble HbS from the sample. The hemoglobin types that remain (HbA, HbA2 and HbF) were measured spectrophotometrically or estimated visually allowing samples to be categorized into three genotypes (AA, AS and SS) as confirmed by hemoglobin electrophoresis. De-identified EDTA blood samples were obtained from Saint Louis University and Cardinal Glennon Children's hospitals and tested in the Department of Clinical Laboratory Science at Saint Louis University. The main outcome measures were turbidity of the solubility solution; color of the supernatant and the material on the surface of the solution following centrifugation; precipitate trapped on the filter paper; absorbance of the filtrate; and hemoglobin electrophoresis patterns. Centrifugation and filtration successfully separated HbS from HbA/A2/F allowing for the differentiation of seven sickle cell homozygotes from sixteen heterozygotes with a sensitivity and specificity of 100%. This method has the potential to reliably distinguish homozygous from heterozygous sickle cell patients and it is fast, inexpensive, and simple. These characteristics make Sickle Confirm a desirable method in developing countries like Haiti and Africa where sickle cell anemia is prevalent and modern diagnostic methods like electrophoresis, HPLC and nucleic acid testing are impractical.

Before the routine use of DNA profiling, blood typing was an important forensic tool. However, blood typing was not very discriminating. For example, roughly 30% of the United States population has type A-positive blood. Therefore, if A-positive blood were found at a crime scene, it could have come from 30% of the population. DNA profiling has a much better ability for discrimination. Forensic laboratories no longer routinely determine blood type. If blood is found at a crime scene, DNA profiling is performed. From Jeffrey's discovery of DNA fingerprinting to the development of PCR of STRs to the formation of DNA databases, our knowledge of DNA and DNA profiling have expanded greatly. Also, the applications for which we use DNA profiling have increased. DNA profiling is not just used for criminal case work, but it has expanded to encompass paternity testing, disaster victim identification, monitoring bone marrow transplants, detecting fetal cells in a mother's blood, tracing human history, and a multitude of other areas. The future of DNA profiling looks expansive with the development of newer instrumentation and techniques.

Objective: The Cumulative Summation of Differences (CUSUM) is a recommended method for determining the consistency of one lot of Activated Partial Thromboplastin Time (APTT) reagent to another. This study investigates the usefulness of the CUSUM as a primary method for determining reagent suitability for APTT testing.

Method: Results for lot comparison, reference range and Ex-Vivo heparin sensitivity studies were obtained using the Beckman Coulter ACL TOP coagulation analyzer. APTT testing was performed using HemosIL SynthASiL w/CaCl and Heparin Xa testing was performed using the HemosIL Liquid Heparin Assay. Samples from normal patients and from patients taking heparin were tested.

Results: The CUSUM calculation showed a difference in APTT reagent lot means that is within the acceptable range for this method, suggesting that the reagents were comparable. Reference range and heparin sensitivity studies demonstrated a clinically significant difference between the two reagent lot numbers tested.

Conclusion: The CUSUM method of evaluating reagent lot variation of APTT reagents should be used with caution as it may not completely reflect the performance of the reagent. Clinically significant differences between reagent sensitivity may not be detected. The results of reference range and heparin sensitivity studies should also be considered when determining the suitability of APTT reagents. In addition, due to research evidence that using the APTT test for monitoring patient anticoagulation therapy is problematic, an evaluation of the benefits of using other study methods and multiple study methods is suggested as well as continued examination of the use of the APTT as the test of choice for UF heparin monitoring.

Recent advances in technology have brought forth an intriguing new tool for teaching hematopoietic cellular identification skills: the digital slide. Although digitized slides offer a number of appealing options for educators, little research has been done to examine how their utilization would impact learning outcomes. To fill that void, this study was designed to examine student performance, skill retention and transferability, and self-efficacy beliefs amongst undergraduate MLS students learning cellular morphology with digital versus traditional slides. Results showed that students learning with digital slides performed better on assessments containing only traditional slide specimens than students learning with traditional slides, both immediately following the learning activity and after a considerable duration of time. Students learning with digital slides also reported slightly higher levels of self-efficacy related to cellular identification. The findings of this study suggest that students learning cellular identification skills with digital slides are able to transfer that skill directly to traditional slides, and that their ability to identify cells is not negatively affected in present or future settings.