About Special (Diagnostic) Tests

 Special Physiotherapy Diagnostic Tests 

    After the examiner has completed the history, observation, and evaluation of movement, special tests may be performed for the involved joint. Many special tests are available for each joint to determine whether a particular type of disease, condition, or injury is present. They are sometimes called clinical accessory, provocative, motion, palpation, or structural tests. 

  

 Special tests should never be used in isolation or as “stand-alone” physiotherapy tests. They should only be considered as part of an overall clinical assessment that includes history, observation, and the rest of the examination. One of the negative parts of special tests is that many clinicians, especially those with less experience, hope that any special tests they use will give them a definitive answer as to what is wrong. A special physiotherapy test may give a definitive answer, more commonly it does not but combined with the other information from the assessment, a clearer picture of the problem arises. 

    These tests, although strongly suggestive of a particular disease or condition when they give positive results, do not necessarily rule out the disease or condition when they give negative results. This depends on the sensitivity and specificity of each test as well as the skill and experience of the clinician. 

    No physical test is 100% reliable, valid, sensitive, or specific. It is better to learn one or two tests well and to be confident and proficient in their use rather than learning all the possible tests used to confirm a certain pathology. The experience of the clinician and the “state” of the patient is important. It means they are useful along with the history and the rest of the examination in making a diagnosis.

Special Test Considerations

    Any special physiotherapy test, regardless of its classification, can be positively or negatively affected by the:

• Patient’s ability to relax
• Presence of pain and the patient’s perception of the
• Presence of patient apprehension
• Skill of the clinician
• Ability and confidence of the clinician during surgery when the patient is unconscious.

 The special tests, although they have an important role to play, should not be used in isolation, nor should they be the single deciding factor in making a diagnosis.

Reliability may be affected

    By cooperation of the patient, which may be influenced by the patient’s ability to relax, tolerate pain, describe apprehension, and show sincerity

    By the skill of the clinician, which may be influenced by experience, his or her ability to relax, and to confidently do the test, and it may be affected by the calibration of equipment.

    If the clinician is unsure that the patient has a particular condition, dysfunction, or disease, then the examiner would want to use a test of exclusion or discovery that has high sensitivity as it will rule out those people who do not have the problem, provided the test’s specificity is equal to or higher than another test testing for the same thing. On the other hand, if the examiner has a high level of suspicion (based on the preceding history, observation, and examination) that the problem is present and wants to confirm that decision (a confirmation test), then the examiner would want a test with higher specificity to “rule in” those people who do have the problem, provided the test’s sensitivity is equal to or higher than another test testing for the same thing. This is especially true if further evaluation or treatment is expensive or dangerous.

    Tests can be more accurately performed right after injury (during the period of tissue shock—5 to 10 minutes after injury), under anesthesia, or in chronic conditions where the pain may be less of a factor. Each examiner tends to use those tests he or she has found to be clinically effective. A clinical test should be viewed as an integral part of a total examination. They should be considered as tests to confirm a tentative diagnosis, to make a differential diagnosis, to differentiate between structures, to understand unusual signs, or to unravel difficult signs and symptoms.

Special Test Uses

• To confirm a tentative diagnosis
• To make a differential diagnosis
• To differentiate between structures
• To understand unusual signs
• To unravel difficult signs and symptoms

    However, the addition of too many special tests only makes the picture more confusing and the diagnosis more difficult. Also, care should be taken when performing these tests, because they are usually provocative tests and will provoke signs and symptoms, including pain and apprehension. Thus, special tests should be done with caution.

    The special test may be contraindicated in the presence of severe pain, acute and irritable conditions of the joints, instability, osteoporosis, pathological bone diseases, active disease processes, unusual signs and symptoms, major neurological signs, and patient apprehension.