No abstract

Intermethod variability in 25(OH)D assays continues to limit our progress toward the establishment of reference values for 25(OH)D in health and our efforts to gain a better understanding of the role of vitamin D insufficiency as a risk factor for disease.

A 21‐year‐old gravida 2, para 1001 female at 39 weeks and 4/7 days gestation was admitted to the labor and birth unit in active labor. She moved to the United States from Pakistan during the last 2 months of her pregnancy. She is a practicing Muslim. Her sister‐in‐law accompanied her. She had an uncomplicated antenatal course, except for iron deficiency anemia (at admission, her hemoglobin was 9.40 g/dl and hematocrit was 29.1%). She had an epidural anesthetic for pain relief. Her first stage of labor was 9 hours, her second stage was 5 minutes, and her third stage was 15 minutes. The baby was born over an intact perineum with Apgar scores of 9 and 9, respectively, and weighed 3,095 g. The baby was placed on the mother's abdomen, and once cleaned and wrapped in a blanket on the infant warmer, the baby was held by the mother. When asked her infant feeding preferences, the mother expressed eagerness to breastfeed. However, before initiation of breastfeeding, the sister‐in‐law asked the midwife permission to feed the baby a sweet (a drop of brown sugar). The sister‐in‐law explained that it was customary in Muslim families that “the first thing to touch the baby's mouth should be something sweet.” After the midwife agreed, the sister‐in‐law said a prayer. As requested by the mother, the baby was fed the drop of sweet. Breastfeeding was initiated within an hour postpartum. She reported exclusively breastfeeding from her birth until her 6‐week postpartum visit.

Objectives-The main objective was to study the acute vascular effects in the hands of normal healthy subjects of a complex vibration spectrum similar to that generated by many industrial hand held tools. The effects of repeated bouts of vibrations and alterations in the intensity of vibration were also studied. Methods-Blood flow was measured by venous occlusion plethysmography with strain gauges. Vibration across a frequency range of 0'4 to > 4000 Hz was generated by a pneumatic chisel and applied to the right hand. Blood flow was measured in both middle fingers, both big toes, or both forearms before, during, and after a two minute period of vibration. Systolic pressure of a finger and heart rate were also measured. Results-Vibration was associated with a significant bilateral reduction in finger and toe blood flow (P < 0.01 and P < 0.03) and a significant increase in heart rate (P < 0.05) but had no effect on forearm blood flow. The finger response was not abolished by repeated bouts of the vibration but was initially most notable during the first minute of vibration. Increasing the intensity of vibration delayed recovery. Conclusions-Hand vibration causes a generalised increase in sympathetic tone in the heart and extremities. This may be a factor in the development of vasospastic disease in habitual users of hand held industrial vibrating tools.

We studied the magnitude, significance, and origin of an analytic bias that emerged between our point-of-care (POC) and our central laboratory (CL) methods for the measurement of hemoglobin A1c (HbA1c) and evaluated the analytic accuracy of 7 commonly used HbA1c methods relative to the National Glycohemoglobin Standardization Program (NGSP) reference method. The POC and CL methods were compared by split-sample analysis of clinical specimens and time series analyses of the HbA1c results reported for a 33-month period. The relative accuracies of 7 HbA1c methods were evaluated using College of American Pathologists proficiency survey results. Long-term drifts in the CL- and POC-analyzed test results caused the median intermethod bias [(POC result)-(CL result)] to increase from -0.4% to -0.9% HbA1c. Systematic biases, drifts in analytic performance over time, and intermethod variability were frequently observed among the 7 NGSP-certified HbA1c methods. Intermethod variability is a potential source of inaccuracy whenever HbA1c results are interpreted relative to universal, fixed, clinical decision thresholds.