Jerk (d(acceleration)/dt) as an operative variable in pneumatic tube transport (PTT).

BACKGROUND: Jerk, the rate of change of acceleration (d(acceleration)/dt), is a known operative variable in public transportation safety, but this term has never appeared in the literature regarding pneumatic tube transport (PTT) and specimen integrity. We investigated profiles of acceleration and jerk for 2 PTT routes within our hospital system. METHODS: Acceleration data were collected for PTT for 2 routes (A, B) using an accelerometer. Acceleration vectors (a) were analyzed in terms of distributions of jerk (da/dt), and distributions of θ, the angle between successive acceleration vectors. RESULTS: Routes A and B had transit times of approximately 300 s. Acceleration vectors (a) ranged in magnitude from 0 to 8 g. For B, a > 1.2 g comprised 29.0% of results, compared to 13.5% of results for A (ratio = 2.1). Jerk ranged from 0 to 94 g/s. For B, jerk > 0.5 g/s comprised 71.9% of results, compared to 32.5% of results for A (ratio = 2.2). θ ranged from 0 to 180 degrees. For B, θ > 5 degrees comprised 59.3% of results, compared to 26.6% of results for A (ratio = 2.2). CONCLUSION: Differences in distribution in acceleration, jerk, and θ ran in parallel as variables for comparison between 2 PTT routes. Jerk and θ are likely to be operative variables in effects of PTT.

Evaluation and operationalization of commercial serum indices quality control material in the clinical laboratory.

BACKGROUND: Evaluation of specimen suitability for downstream analytical testing and identification of potential interferents in the clinical laboratory is critical for the generation of actionable clinical results. Within the clinical laboratory, hemolysis, icterus, and lipemia are commonly assessed spectrophotometrically. While clinical laboratories rely on analyte-specific quality control (QC) materials to monitor test or instrument performance, QC materials evaluating specimen integrity checks are infrequently implemented. METHODS: Using commercially available specimen integrity materials, we evaluated the Bio-Rad Liquichek™ Serum Indices product on Roche cobas® c701 analyzers at a large academic medical center. Target arbitrary values for the hemolysis, icterus, and lipemia QC materials were 200, 20, and 500, respectively. Means, standard deviations (SD), and coefficients of variation (%CV) were established for hemolysis, icterus, lipemia, and non-interfered QCs, and performance was monitored over a 60-day period. RESULTS: Across four c701 instruments, all QC materials performed well, with %CVs ≤ 1.76%, 4.51%, and 3.46% for hemolysis, icterus, and lipemia QC, respectively. CONCLUSIONS: The Bio-Rad Liquichek Serum Indices product can serve as an effective means of monitoring specimen integrity checks in a manner congruous with existing QC programs.

HIV-1 viral load testing in resource-limited settings: Challenges and solutions for specimen integrity.

HIV-1 viral load (VL) testing is a crucial element in providing an antiretroviral treatment monitoring program. The success of these programs depends on the availability and quality of the VL testing services. There are several pre-analytic factors which can affect the quality of VL testing. Many of the challenges faced by resource-limited countries result in a compromise of specimen integrity, thus limiting widespread access to VL monitoring. The various logistic and financial challenges that exist are not insurmountable and several innovative solutions currently exist to overcome these barriers to providing widespread VL testing. This review summarizes the VL testing challenges in resource-limited settings and provides an overview of potential solutions including testing dried blood spots, dried plasma spots, plasma separation cards and the use of point of care tests.

Lesion Retrieval, Specimen Handling, and Endoscopic Marking in Colonoscopy.

Retrieval of lesions after endoscopic polypectomy enables histopathologic analysis and guides future surgical management and endoscopic surveillance intervals. Various techniques and devices have been described with distinct advantages and disadvantages to accomplish retrieval. Appropriate histopathologic analysis depends on lesion handling and preparation. How lesions are handled further depends on size, endoscopic appearance, and removal technique. Endoscopic marking or tattooing is a well-described process that uses dye mediums to leave longstanding marks in the colon. Techniques, dye mediums, and locations within the colon influence tattoo approach.

Pre-examination factors affecting molecular diagnostic test results and interpretation: A case-based approach.

BACKGROUND: Multiple organizations produce guidance documents that provide opportunities to harmonize quality practices for diagnostic testing. The International Organization for Standardization ISO 15189 standard addresses requirements for quality in management and technical aspects of the clinical laboratory. One technical aspect addresses the complexities of the pre-examination phase prior to diagnostic testing. METHODS: The Committee for Molecular Diagnostics of the International Federation for Clinical Chemistry and Laboratory Medicine (also known as, IFCC C-MD) conducted a survey of international molecular laboratories and determined ISO 15189 to be the most referenced guidance document. In this review, the IFCC C-MD provides case-based examples illustrating the value of select pre-examination processes as these processes relate to molecular diagnostic testing. Case-based examples in infectious disease, oncology, inherited disease and pharmacogenomics address the utility of: 1) providing information to patients and users, 2) designing requisition forms, 3) obtaining informed consent and 4) maintaining sample integrity prior to testing. CONCLUSIONS: The pre-examination phase requires extensive and consistent communication between the laboratory, the healthcare provider and the end user. The clinical vignettes presented in this paper illustrate the value of applying select ISO 15189 recommendations for general laboratory to the more specialized area of Molecular Diagnostics.

Validation of hemolysis index thresholds optimizes detection of clinically significant hemolysis.

OBJECTIVES: Automated hemolysis index (HI) measurement has standardized the identification and gradation of sample hemolysis. METHODS: This study evaluates whether clinically significant changes in the concentration of intracellular analytes occur at manufacturer-recommended automated HI thresholds (HI ≥3, >25 mg/dL hemoglobin). RESULTS: Adult outpatient results for serum potassium (K+), magnesium (Mg), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) were analyzed. Mean ± SD analyte concentration and distribution within the reference interval (RI) were calculated for each HI group (1-7). Potassium results with an HI of 4 or more demonstrated clinically significant differences (≥0.5 mmol/L) in mean K+ concentration and RI classification compared with non-hemolyzed samples (HI = 1). LDH and AST showed clinically significant differences (+20%) for an HI of 3 or more. For Mg, only the group with an HI of 7 demonstrated a clinically significant difference (>25%); however, the number was low. CONCLUSIONS: Mean measured potassium concentrations are not clinically significantly affected by hemolysis at the manufacturer-recommended HI threshold, while AST and LDH are. Aligning reporting of sample hemolysis with clinically significant changes provides clinically meaningful alerts regarding this common pre-analytic error.