diagnosis, the process of determining the nature of a disease or disorder and distinguishing it from other possible conditions. The term comes from the Greek gnosis, meaning knowledge.

The diagnostic process is the method by which health professionals select one disease over another, identifying one as the most likely cause of a person’s symptoms. Symptoms that appear early in the course of a disease are often more vague and undifferentiated than those that arise as the disease progresses, making this the most difficult time to make an accurate diagnosis. Reaching an accurate conclusion depends on the timing and the sequence of the symptoms, past medical history and risk factors for certain diseases, and a recent exposure to disease. The physician, in making a diagnosis, also relies on various other clues such as physical signs, nonverbal signals of distress, and the results of selected laboratory and radiological and other imaging tests. From the large number of facts obtained, a list of possible diagnoses can be determined, which are referred to as the differential diagnosis. The physician organizes the list with the most likely diagnosis given first. Additional information is identified, and appropriate tests are selected that will narrow the list or confirm one of the possible diseases.

Diagnostic services basically refer to such services, which are used to determine the cause of an illness or a condition of a patient. Diagnostic services operate at three levels-

• The first or basic level, in which simple observations are made.
• The next level is the intermediate level. Simple tests such as X-Rays and blood tests are done at this level.
• The third level is a complex one. It consists of tests such as MRI and endoscopy which are higher levels tests.

If your doctor prescribes certain tests, yourfirst question obviously will be why you must undergo these tests. Here are the major benefits of these diagnostic laboratory services.

1. Diagnostic services are important as they help doctors to determine the exact cause of the patient’s illness and discomfort. In a lot of cases the symptoms are so similar that the doctor may sometimes be confused. It is then that the different diagnostic laboratory services become useful.
2. In most less developed and developing countries,diagnostic services have played an important role in reducing incidences of certain widespread diseases like hepatitis and tuberculosis.
3.  In the pathological laboratories the tests are performed under the supervision of trained personnel like pathologists and radiologists. Sometimes, when it comes to identifying the major cause of a disease they are more aware than doctors and healthcare personnel.
4. In times when diagnostic laboratory services were not so advanced the doctors depended on the patient’s symptoms to identify the problem and prescribe the medication. Many a times the symptoms weren’t all that clear and the patient ended up being treated for a wrong problem. But with advancement of technology and medical science this is no longer an issue. The diagnostic centres today have several tests to offer. Doctors ask the patients to undergo the relevant tests before reaching a conclusion and prescribing medication.
5. There are certain disorders which cannot be identified in its initial stage solely on the basis of visible symptoms. This is where diagnostic services come in handy. It is through these tests that doctors are often able to identify issues, which even the patient himself may not be aware of.