What Is Diagnostic Reliability?

Use clinical data, laboratory tests, X-rays and other more scientific and accurate measures to distinguish the sick from the non-sick. For the diagnostic test "patient with disease", it can be determined as a patient, and the next step of treatment can be performed in time.

Diagnostic test

Right!

Use clinical data, laboratory tests, X-rays and other more scientific and accurate measures to distinguish the sick from the non-sick. For the diagnostic test "patient with disease", it can be determined as a patient, and the next step of treatment can be performed in time.

Diagnostic tests are mainly used in the diagnosis of diseases, follow-up of diseases, evaluation of curative effects, and monitoring of toxic and side effects of drugs. Clinicians, however, cannot avoid a reliable diagnosis based on experience alone. Failure to provide timely and effective treatment to patients may even cause irreparable losses. Mastering scientific research and evaluating diagnostic test methods can lay the foundation for selecting a reasonable diagnostic method, and at the same time avoid errors caused by experience alone.

1 Blind comparison with standard diagnostic methods (gold standard) is required. Standard diagnostic methods are reliable, recognized diagnostic methods that correctly distinguish between diseased and disease-free. The standard diagnostic methods commonly used in clinical practice include pathological examination, surgical findings, and positive conclusions obtained from long-term follow-up cases. For example, the standard diagnostic method for diagnosing coronary heart disease is coronary angiography, the standard method for diagnosing nephritis is renal tissue biopsy and autopsy, and the standard method for diagnosing gallstones is surgical observation. The specific method is to use standard diagnostic methods to divide the cases into actual diseased and non-disease groups under the condition of "blind", and then compare the diagnostic test to be evaluated with the diagnosis results of the same case, and then list the four grid tables , You can get the true and false positive and true and false negative results, as shown in Table 33-1, and calculate the sensitivity, specificity, predicted value and correct index.

1. Validity or accuracy requires a diagnostic test to have the ability to correctly identify a case with or without a disease. This degree of reflecting the actual situation of the disease is called authenticity, also known as accuracy.

2. Reliabiliy, repeatability or precision refers to the stability of a diagnostic test to obtain the same results when repeated under the same conditions. In clinical practice, reliability is generally expressed by the coincidence rate.

3. Predictive value Sensitivity and specificity are characteristics of a diagnostic test, and physicians should consider these characteristics when deciding whether to use a test. Once a diagnostic test is adopted, the physician must carefully consider the significance of the test results. If a positive result is obtained, what is the probability of suffering from a disease; if a negative result is obtained, what is the probability of not suffering from a disease? This is the predicted value. Positive predictive value refers to the proportion of true positives in the test positive cases; negative predictive value refers to the proportion of true negatives in the test negative cases.

1. Select the population with high prevalence (high-risk population)

2. Serial test is also called series test.