A considerable number of diseases, for example, oncological, endocrine, and urinary tract infections, can develop for a long time without causing any complaints in the patient. We often do not pay attention to their common symptoms: rapid fatigue, constant weakness, low-grade fever and others, explaining them by fatigue at work, vitamin deficiency, nervous experiences, “critical” days... With the current level of development of medical services, you have the opportunity take tests after receiving a referral from a doctor, or on your own initiative. However, you need to understand when and what tests you need, and what the data obtained in the laboratory mean, and which specialist you now need to contact. This book will help you decipher the mysterious language of medical terms and numbers. Only with such a conscious approach to your health can you detect the development of the disease at an early stage.