Final answer:
The physician ordered lab tests to establish a differential diagnosis to identify Gina's ailment since many diseases can produce similar symptoms. Additional tests like genetic analysis or MRIs are often needed to accurately diagnose a patient. These tests offer further evidence towards confirming a disease.
Step-by-step explanation:
Gina's physician ordered laboratory tests that would enable him to establish a differential diagnosis to identify the cause of her signs and symptoms. Medical professionals rely heavily on the analysis of signs and symptoms, often supported by laboratory tests, to prescribe the correct treatment. Since many diseases have overlapping symptoms, additional tests such as genetic analysis, isolation of bacteria, or direct Gram stain are essential to pinpoint the exact disease. For example, Kayla's doctor ordered an MRI and blood tests to rule out SLE or Lyme disease and considered further tests after inconclusive results. Similarly, John's physician ordered various samples alongside chest radiography to delineate the cause of his illness. Diagnostic tests are crucial as they provide further evidence towards the most accurate diagnosis.