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A comparison of penicillin excretion when equivalent quantities of the drug are given orally or parenterally indicates that approximately 60 per cent. urinary excretion occurs after parenteral administration, whereas 14 per cent. urinary excretion occurs following oral ingestion. That destruction by gastric acidity is not primarily responsible for this difference is indicated by the fact that administration of penicillin directly into the duodenum does not greatly alter the amount of penicillin excretion. Evidence indicating that the majority of orally administered penicillin is destroyed by the body proper is discussed.

We evaluated the utility of chloride titrator sticks for facilitating the assessment of dietary salt intake, in a systematic series of clinical trials. These inexpensive devices were applied daily to 24-h or nocturnal urine specimens, thereby avoiding the inter- and intra-subject variability in salt excretion which confounds the use of occasional 24-h urine collections. Chloride and sodium concentrations in urine were highly correlated (r greater than 0.92) in either nocturnal, diurnal, or 24-h collections. The quantitative chloride titrator estimates and measured chloride concentrations were highly correlated as well (r greater than 0.99). The qualitative chloride titrator was graded on a simple scale, and was successfully employed by outpatients attempting to limit their salt intake. Commonly used antihypertensive medications did not interfere with the determinations. Additional chloride intake, such as supplemental potassium chloride, interfered with estimates of salt ingestion, but if the daily amount of potassium chloride supplement was constant, adjustments in interpretation could be made. Renal insufficiency introduced a systematic over-estimation of salt intake by the qualitative chloride tirator, but only at high salt intakes. Relative estimates of salt intake in subjects with renal failure were still possible. We conclude that chloride titrators can facilitate the management of patients who require a prescribed salt intake.

A simple, specific, sensitive, and speedy test for glucose in urine has been described. This enzymatic test based on the activity of glucose oxidase and peroxidase is called Clinistix. Data are presented to show that the test has a high accuracy with both positive and negative specimens.

A color reaction of protein has been formulated into two simple colorimetric tests for protein in urine; one is a tablet test, consisting of a salicylate buffer and bromphenol blue, and the other is a strip test, consisting of a paper strip impregnated with a citrate buffer and tetrabromphenol blue. The basic principle in both tests is that of "protein error of indicators." Experiments with approximately 5000 urines, taken from both hospital patients and normal subjects, reveal that these tests are simple, rapid, accurate, sensitive, specific, and capable of being used with turbid urines.

Results are presented of a comparative study of several methods for detection of ketone bodies in urine involving nearly 10,000 tests on urines containing no ketones, naturally occurring ketones, and added acetoacetate. Acetest (a tablet nitroprusside test) and Ketostix (a strip nitroprusside test) are more specific and accurate, and have the proper sensitivity in comparison with test tube Rothera nitroprusside modifications or the ferric chloride test. Both the tablet and strip are also satisfactory for detection of ketones and serum or plasma. The tablet test may be used with whole blood for detection of ketonemia.

A triple-test strip for the simultaneous estimation of protein, glucose, and pH in urine with one simple dip-and-read operation is described. The three results can be obtained in little more than 10 seconds' time. Each of the three tests is a colorimetric reaction, and each is accompanied by a color chart for standardized results. A total of 12,674 results obtained in blind testing by experienced and inexperienced operators indicates that all three tests give accurate, reliable performance, as compared with other laboratory methods.

A colorimetric test procedure called Mega-Diastix is described for detection and measurement of glucose in urine. The test is designed for use by diabetic patients with impaired vision. Data establishing the performance capabilities of this rapid, convenient test are presented. As an internal standard, the recommended procedure utilizes effervescent control tablets for preparation of simulated urine. Also described is a touch fermentation test for detection of urinary glucose by totally blind patients. Data are given that demonstrate the accuracy and ease of performance of this test, which entails a rapid yeast fermentation. An internal standard is also incorporated into the procedure for this test.

The physician's office laboratory is an important adjunct to quality patient care. Dry chemistry reagents and the instrumentation used with them provide an ideal mechanism to give the patient a timely, relatively inexpensive work-up. An office laboratory can save the physician and his or her staff many frustrations. But unless the physician's office laboratory director makes use of the assistance of laboratorians and manufacturers in setting up good quality assurance systems along with the choice of dry chemistry system, the director may merely replace his or her frustrations with new ones. The limitations of an office laboratory are far outweighed by the benefits in quality patient care.

To develop methods of estimating sodium intake in free-living persons, we gave normal volunteers mean sodium intakes of 65, 110, and 200 mEq/day. The intake was randomly varied about each mean by an SD of 12.5% daily. Twenty-four-hour and night urinary sodium excretion were measured. Night urinary sodium excretion was also estimated by means of inexpensive quantitative and qualitative chloride titrator strips. The latter required no timed urine collection. A total of three 24-hour urine collections were necessary to differentiate the regimens with 95% accuracy. Three night urinary sodium excretory estimates by the quantitative chloride titrator provided 79% accuracy in identifying the level of dietary sodium intake. By applying the qualitative chloride titrator every other day, the dietary regimens could be differentiated with 95% accuracy. These techniques were not only useful in estimating sodium intake, but also provided a simple means of documenting compliance to sodium restriction. Patients should have no difficulty in applying these methods themselves in a home setting.

The extremely high incidence of salicylate intoxication makes it desirable to have a screening test available. Such a procedure should be simple and rapid enough to be used routinely on all admission and emergency cases since salicylate intoxication may not be suspected. This report describes studies with a stick test used on urine and serum. Test results agree well with quantitative measurements. Specimens tested included urine and serum from dogs and human beings after experimental administration of aspirin as well as samples from cases of salicylate intoxication or high therapeutic salicylate levels. The test strip develops an immediate brownish purple color with as little as 20 mg. per cent free salicylate. Data are presented to show that reliable results are obtained with the test even by inexperienced individuals.

A standardized dip-and-read test for the detection of ketone bodies is described. This simplified nitroprusside test has a reading time of only 15 sec. The test is of value in assessing the severity of human ketosis since it can be used to determine the level of ketone bodies in both urine and serum. Testing urine from small experimental animals and testing cow's milk for early detection of bovine ketosis are easily accomplished with the stick test. The sensitivity and reactivity of the test appear to be the same in all body fluids studied. Data are presented which establish the accuracy, the reliability, and the utility of the stick test as a tool in scientific investigations.