Tests to Safeguard Health
Saturday, October 11th, 2008For more than a generation the staff of the health department laboratory has worked to promote the public health. This they have done by testing drinking water for evidence of bacterial contamination, by analyzing milk and other dairy products for purity and nutritive value, by checking food handlers for evidence of communicable disease, and the like.
More recently, the clinical pathologist in his laboratory has developed techniques for evaluating the personal health of the individual. By testing apparently healthy individuals at regular intervals he has learned to detect disturbances of function before organ disease has occurred. Modification of diet or habits may then correct the functional disturbance before actual illness develops.
The diseases that may be prevented by these means are the chronic diseases, slow in onset and dangerous when undetected, especially those which tend to appear in middle age and to cause prolonged illness and death.
The physician must give careful thought to the selection of laboratory tests to be used in the health examination. In general the tests which are most useful are “screening tests” which provide a broad surveyor’ profile of the various organ systems, especially those systems which are most apt to be affected by chronic diseases. If one of these tests yields an abnormal result, the physician then extends the examination in order to pinpoint the diagnosis.
Recommended tests will differ somewhat for different individuals, depending upon their history of familial diseases, prior illnesses, occupational or environmental hazards, social contacts, diet, habit, age and sex. Since most persons undergoing annual physical examinations are mature adults, certain tests are commonly used for all, and to this group are added other tests that are appropriate for the specific individual.
There are a great many tests which may be employed with benefit in health maintenance, but considerations of cost, convenience and safety to the patient tend to reduce the list to those procedures most likely to yield useful information.
Ideally, patients should be in a baseline state at the time their specimens are collected for laboratory examinations, since certain blood chemical studies may be influenced by food intake and physical activity. If specimens are always taken before breakfast and after a good night’s sleep, the results will reflect the true basal state and can be compared to normal values.
By regular annual repetition of the whole series of laboratory tests, it is sometimes possible to recognize a beginning functional disturbance, even before the test result is definitely abnormal. Thus if a man in his middle thirties has shown consistently a blood cholesterol of 175-200, and then in his forties his cholesterol values rise to 250, it would seem wise to give consideration to this change in spite of the fact that the new value is still not definitely abnormal.
In the following section are listed certain tests and procedures that are commonly used as part of the annual physical examination. For a brief explanation of the various tests, see definitions at the end of this chapter.
Tags:bacterial contamination, chronic diseases, environmental hazards, middle age, nutritive value screening tests