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Self testing as a phase of health delivery has been utilized for approximately 70 years, but within the last two decades there has been an increasing interest in and use of self testing. The practice of self testing has a sound basis, which involves medical relevancy, cost containment, and convenience. It is reasonable to anticipate that self testing will increase in the future as medical needs and available procedures are established. The clinical chemist, the physician, and the industrial producer of test systems all have important roles in self testing. The clinical chemist, whether in a hospital laboratory or in an industrial setting, has the responsibility to create new self-testing procedures that represent expansion and improvement over those currently available. The clinical chemist also has a critical role in the evaluation of new self-testing procedures and in validating their capability of providing high-quality information. The provision of quality-assurance programs and proficiency programs for the user can most effectively be carried out by clinical chemists. The clinical chemist can also play an important role as a consultant, teacher/educator, and trouble shooter in recognizing and helping solve problems that may appear in various areas of self testing. The classic role of the physician has been to diagnose disorders of the patients and provide therapy for effective care. The role of the physician in self testing is quite comparable to his usual role, since the ultimate diagnosis of disease will be carried out by the physician and he will continue to be the source for definition of therapy. A major portion of self testing will be carried out with the recommendation of a physician, and he will maintain a role in the interpretation of results. The physician needs to be familiar with self-testing practices and procedures and be prepared to provide interpretation of self-testing results. Industry supplies an increasing proportion of reagent systems and instruments for the clinical laboratory. The supplying of reagent systems and small instruments for self testing is almost completely a role of industry. The creation and funding of new products for self testing will be provided by industry to a large extent. A critical function of industry is to provide high-quality products and efficient customer service to the self-testing component of health delivery. We have each played a role in self testing over a period of approximately 40 years. During this period self testing has become an important phase of clinical laboratory practice.(ABSTRACT TRUNCATED AT 400 WORDS)

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 simplified analytical procedure for the determination of guanase in serum or plasma at 245 mµ is described. Effects of experimental hepatic injuries in dogs on serum guanase levels and the possible clinical utility of the enzyme serum guanase are also discussed.

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 simple dip-and-read strip test for detection of phenylketonuria is described. This test contains ferric and magnesium ions and an acid buffer. It is called PHENISTIX. When the strip is moistened with urine it gives a gray to blue color with samples which contain phenylpyruvic acid, the intensity being proportional to the concentration of this constituent. A color chart provides for standardization of results and reproducible reports. Comparison of the performance of the test with conventional laboratory procedures has been carried out on over 1900 samples as tests on unknowns. The new test is reliable for the recognition of phenylketonuria and has some advantages over conventional laboratory procedures.

A collaborative study has been made on the use of the QUANTAB Chloride Titrator for monitoring salt concentration in meat, fish, and cheese. Data from 12 collaborators on 6 samples show good agreement of results from all of the collaborators on all of the samples. The QUANTAB method has been adopted as a procedure.

The QUANTAB Chloride Titrator is a convenient tool for monitoring salt concentration in meat, fish, and cheese; it provides meaningful information on the salt content of food products for easier quality control during processing. Data are given showing typical results for various types of meat, fish, and cheese; these results compare favorably with those from the official AOAC Volhard methods.