Review test results promptly. Report and interpret test outcomes correctly. Abnormal test patterns or trends can sometimes provide more useful information than single test outcome deviations. Conversely, single test results can be normal in patients with a proven disease or illness.
Look at both current and previous test results and review the most recent laboratory data first and then work sequentially backward to evaluate trends or changes from previous data. The patient’s plan of care may need to be modified because of test results and changes in medical management.
Recognize abnormal test results and consider the implications for the patient in both the acute and the chronic stages of the disease as well as during screening.
The greater the degree of test abnormality, the more likely the outcome will be more serious.
Consider the impact of medications when tests are abnormal. Use of over-the-counter drugs, vitamins, iron, and other minerals may produce false-positive or false-negative test results. Patients often do not disclose all medications they use, either unintentionally or deliberately. Commonly prescribed drugs that most often affect laboratory test outcomes include anticoagulants, anticonvulsants, antibiotic or antiviral agents, oral hypoglycemic drugs, hormones, and psychotropic drugs. Consult a pharmacist or Physicians’ Desk Reference source about drugs the patient is taking. Be aware that patients who are addicted to drugs or alcohol may not provide accurate, reliable information about their use of these agents. In the same vein, sometimes athletes may not disclose their use of performance-enhancing drugs.
Consider biocultural variations when interpreting test results. See Table 1.8 for examples of some common variations.
Evaluate age-related variables and test outcomes; consider changes in physiology as the various body organs age (e.g., heart, lungs, kidneys).
Clinical Alert
Correct test interpretation requires knowledge of all medications the patient is taking.
Support the patient and their significant others in understanding and coping with positive or negative test outcomes.
Recognize that critical values may pose an immediate threat to the patient’s health status. Report these findings to the attending physician or other designated healthcare provider immediately. Carefully document results and actions taken as soon as possible.
Nearly all tests have limitations. Some tests cannot predict future outcomes or events. For example, an ECG cannot predict a future myocardial infarction; it can merely tell what has already occurred.
Devastating physical, psychological, and social consequences can result from being misdiagnosed with a serious disease because of false-positive or false-negative test results. Major alterations in lifestyles and relationships without just cause can be a consequence of these clinical aberrations (e.g., misdiagnosis of HIV or syphilis).