A rapid quantitative capillary tube enzyme immunoassay for human chorionic gonadotropin in urine.

A quantitative capillary tube enzyme immunoassay (CTEIA) method for the determination of human urinary chorionic gonadotropin (hCG) has been developed. The method utilizes an antibody-coated capillary tube through which the test fluid is passed and a urease-labelled second antibody in an immunometric format. Any hCG in the test solution is 'captured' by the immobilized antibody which is hybridoma derived and specific for the beta-subunit of hCG. The second hCG-specific antibody, conjugated to the enzyme urease, is used to detect the captured hCG on the internal surface of the capillary tube. The amount of urease bound to the surface is determined by the introduction of a substrate solution containing urea and the pH indicator bromothymol blue. The rate of colour change, from yellow to blue, caused by the release of ammonia from urea by urease, is determined in a spectrophotometer using a cell holder adapted to accommodate capillary tubes. The initial rate of absorbance change is directly proportional to the concentration of hCG in the sample in the range 0-100 mIU/ml. The test can detect concentrations of hCG as low as 10 mIU/ml in a total elapsed time of 5 min.

Evaluation of the revised NIOSH lifting equation. A cross-sectional epidemiologic study.

STUDY DESIGN: A cross-sectional study of the 1-year prevalence of low back pain was conducted in workers employed in manual lifting jobs. OBJECTIVES: To provide epidemiologic data to determine the correlation between the prevalence of low back pain and exposure to manual lifting stressors, measured with the lifting index component of the revised lifting equation from the National Institute for Occupational Safety and Health (NIOSH). SUMMARY OF BACKGROUND DATA: The NIOSH lifting equation has been proposed as a practical, yet valid tool for assessing the risks of low back pain caused by manual lifting. To date, however, there have been few studies in which the effectiveness of the equation to identify jobs with elevated rates of low back pain has been evaluated. METHODS: Fifty jobs from four industrial sites were evaluated with the NIOSH lifting equation. A symptom and occupational history questionnaire was administered to 204 people employed in lifting jobs and 80 people employed in nonlifting jobs. Regression analysis was used to determine whether there was a correlation between the lifting index and reported low back pain. RESULTS: As the lifting index increased from 1.0 to 3.0, the odds of low back pain increased, with a peak and statistically significant odds ratio occurring in the 2 < lifting index < or = 3 category (odds ratio = 2.45). For jobs with a lifting index higher than 3.0, however, the odds ratio was lower (odds ratio = 1.45). CONCLUSIONS: Although low back pain is a common disorder, the lifting index appears be a useful indicator for determining the risk of low back pain caused by manual lifting.

Accuracy of measurements for the revised NIOSH lifting equation. National Institute for Occupational Safety and Health.

Twenty-seven non-ergonomists who participated in a one-day training session on the use of the NIOSH lifting equation (NLE) were subsequently tested on a simulated lifting task eight weeks later to determine their accuracy in measuring the variables. Analysis of the results indicate that (1) inter-observer variability was small, especially for the most important factor (i.e. horizontal distance); (2) individuals can be trained to make measurements with sufficient accuracy to provide consistent recommended weight limit and lifting index values; and (3) measurement of the coupling and asymmetric variables were the least accurate.

An ergonomics evaluation of cashier work activities at checker-unload workstations.

The ergonomic suitability of the 'over-the-counter' (OTC) or 'checker unload' workstation for grocery-scanning operations has been questioned by a number of ergonomists, safety and health professionals, and retail food industry executives in the USA. There is concern that requiring cashiers to remove grocery items directly from the customer's cart for scanning exacerbates the risk of musculoskeletal disorders associated with this job. For this reason, a study was conducted to determine whether supermarket cashiers are exposed to increased biomechanical stress due to the use of checker-unload workstations for standing work. The work activities of 12 grocery cashiers from three supermarkets were recorded on videotape. Postures and movements associated with the scanning task were visually evaluated and compared with those of 10 grocery cashiers using a front-facing, customer-unload workstation examined in a previous study. The results indicate that use of the checker-unload workstation places additional stresses on the cashier beyond those imposed by customer-unload checkstands. Specifically, the task of removing groceries directly from the cart for scanning increases the frequency of long reaches, awkward shoulder postures, and lifts. These stresses can be mitigated by eliminating checker-unload operations and providing checkstands with conveyor belts for delivering groceries to the cashier. Implementing additional workstation modifications and encouraging cashiers to adopt alternative work practices also may reduce the frequencies of awkward postures and stressful motions associated with this checkstand design.

The occupational health status of hired farm workers.

The U.S. hired farm work force presently is two-thirds foreign-born: mostly young Mexican men with low educational attainment who neither read nor write English. Sixty percent earn so little that they and their families live in poverty. Four of ten migrate to find work, 33% are not authorized to work in the U.S., and 25% work for a labor market intermediary, usually a labor contractor. Few hired farm workers have health insurance of any kind and, despite low incomes, relatively few seek or receive government benefits. Government regulation of the workplace exempts agricultural employers from numerous provisions that apply to other industries; for example, agriculture is exempt from portions of the Fair Labor Standards Act, allowing children as young as age 12 to work in the fields, and employers with 10 or fewer employees are exempt from OSHA regulation. Only 12 states require farm employers to carry workers' compensation insurance. While hired farm workers face significant safety and health risks, there are major gaps in existing research covering this occupational group. An ad hoc task force convened by NIOSH developed a prioritized agenda for occupational safety research in this population: musculoskeletal disorders, pesticide-related conditions, traumatic injuries, respiratory conditions, dermatitis, infectious diseases, cancer, eye conditions, and mental health.

Occupational risk of Mycobacterium tuberculosis infection in hospital workers.

We conducted a 4-year (1/89-12/92) retrospective cohort study among employees at a large metropolitan hospital where a nosocomial outbreak of multidrug-resistant tuberculosis (TB) had occurred. We compared the risk of tuberculin skin test (TST) conversion among employees who worked on wards where patients with culture-confirmed TB were cared for ("exposed") with the risk among employees who worked on wards with no such patients ("unexposed"). Exposed employees had a higher 4-year risk of TST conversion (14.5%) than unexposed employees (1.4%) (adjusted relative risk 13.4; 95 percent confidence interval 5.1-35.2). Exposed employees had significantly higher risks of conversion than unexposed employees during 1989-91, but not for 1992. Among the exposed, ward clerks had a risk of conversion (15.6%) only slightly lower than nurses (18.2%). We conclude that employees who worked in areas where patients with active M. tuberculosis infection were cared for, including workers who did not provide direct patient care, had a higher risk of TST conversion than employees who did not work in these areas. Reasons for the decline in risk over time include outbreak termination, fewer admissions of patients with TB, implementation of effective infection control measures, and possible resistance to infection in some members of the study population.