Novel approach to the design of a pediatric microanalytical laboratory

Abstract Instrumentation is developed for the precise sampling of microsamples of human plasma. This includes a sampler-diluter using polished glass plungers and an inexpensive but efficient sample dispenser capable of dispensing several different solvents simultaneously. These two instruments are coupled so that they can transfer and dilute samples from rack to rack or from turntable to turntable. A dispenser station is also described which permits the adding of reagents to 60 tubes/min using the multiple dispenser. An automated centrifuge is also reported which depends upon the rotation of conical plastic containers on their central axis at high speeds to achieve sedimentation of particles such as erythrocytes or precipitates. These containers are moved into and out of a centrifugal field automatically. The containers are centrifuged for approximately 1 min. This is adequate because of the high rate of rotation (12,000–20,000 rpm). The instrumentation is applied to develop precise procedures for glucose, urea, protein, bilirubin, Na, K, Cl, Ca, and Mg in specimens taken from the fingertip of newborn infants. In each case provision is made to remove interference from bilirubin, hemolysis, protein and lipemia. A highly sensitive method for glucose is described using 3 μl of specimen. Alkaline copper is reduced and the color cuprous ion makes with bicinchoninate is measured at 560 nm. The methodology compares favorably, statistically, with preferred macrotechniques.