An improved method for the automated determination of urine calcium.
The problems of accurately determining urine calcium are described. The basic technique described is little changed from that originally used by Clark and Collip but the pitfalls encountered when applying this to automated procedures are demonstrated and a means of overcoming them proposed.
EVALUATION OF PROCEDURES FOR URINARY CALCIUM.
In a comparative study of urinary calcium methods, many of the recently proposed procedures proved either impractical or invalid in our hands. A preliminary isolation of the calcium as the oxalate, followed by perchloric acid oxidation of the oxalate seemed to be the simplest procedure whereby urinary calcium could be put in a state suitable for chelometric titration. The isolated calcium could also be titrated with considerable precision and accuracy by a modified procedure with a derivative automatic titrator which is available commercially.

It was suggested from our observations that too little attention has been directed towards the problems imposed by the occurrence of calcium precipitates in urine. An untreated 24-hr. urine specimen is not suitable for direct analysis of calcium by chelometric titration, by colorimetric analysis, by emission flame photometry, or by atomic absorption flame photometry because these methods do not give a true measure of the calcium in the precipitate. Boiling for 5 min. with 1 part concentrated nitric acid to 25 parts urine proved a suitable means for completely dissolving the calcium precipitate.
A Four Day Trial of Technicon SMA 12/60 at Glasgow Royal Infirmary
The Technicon SMA 12/60 is a continuous flow analyser which determines 12 constituents of serum simultaneously at a sample rate of 6O/hour. These constituents are calcium, inorganic phosphorus, glu­ cose, blood urea nitrogen (BUN), uric acid, choles­ terol, total protein, albumin, total bilirubin, alkaline phosphatase, lactic dehydrogenase (LDH) and glu­ tamic oxalacetic transaminase (GOT). The machine was set up during the weekend of 26th~27th April, 1969 by members of the staff of Technicon Instruments Co. Ltd. and the trial started on 28th April. On this day it soon became obvious that the inorganic phosphorus channel was not per­ forming correctly. The fault (in a reagent) was corrected during the morning of 29th April. The­ trial ended at mid-day on 2nd May so the effective time of the trial was four days. During this time 800 specimens were analysed. Because of the multiplicity of substances being analysed it is virtually impossible to make use of primary standards so the instrument is calibrated using a reference serum with values ascribed by the manufacturer. The manufacturers claim that channels are 'Iinearised' (with the exception of the G.O.T. channel, where the chart is printed in a non­ linear scale to compensate) and that a two point calibration-zero and a high level ofeach constituent is sufficient for calibration of each channel. Before the trial began Technicon supplied refer­ ence serum which was analysed for 11 of the 12 constituents by our routine methods. The ascribed values were not then known. The mean values found and those ascribed are shown in Table I.