The influence of storage time and temperature on the measurement of serum, plasma and urine osmolality.

Background: Many clinical laboratories require that specimens for serum and urine osmolality determination be processed within 3 h of sampling or need to arrive at the laboratory on ice. This protocol is based on the World Health Organization report on sample storage and stability, but the recommendation lacks good supporting data. We studied the effect of storage temperature and time on osmolality measurements.

The impact of repeat-testing of common chemistry analytes at critical concentrations.

Background: Early notification of critical values by the clinical laboratory to the treating physician is a requirement for accreditation and is essential for effective patient management. Many laboratories automatically repeat a critical value before reporting it to prevent possible misdiagnosis. Given today's advanced instrumentation and quality assurance practices, we questioned the validity of this approach.

The cardiovascular risk marker asymmetric dimethylarginine is elevated in asymptomatic, untreated HIV-1 infection and correlates with markers of immune activation and disease progression.

Background: As lifespan in HIV infection increases, cardiovascular disease has emerged as a cause of morbidity and mortality. Asymmetric dimethylarginine is an established marker of endothelial dysfunction and predicts cardiovascular events. The role of asymmetric dimethylarginine in HIV-related cardiovascular disease has not been established.