Diagnostic accuracy

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Main PageDiagnostic accuracy

Diagnostic accuracy

Specificity and sensitivity

The majority of studies which have evaluated the diagnostic accuracy of dermoscopyDermoscopy is a non invasive diagnostic method. have relied on calculation of specificity and sensitivity, by comparing the diagnosisThis glossary term has not yet been described. made by dermoscopy with the histopathological diagnosis.

  • Specificity: the proportion of benignThis glossary term has not yet been described. pigmented skin lesions that are correctly identified by dermoscopy
  • Sensitivity: the proportion of melanomas that are correctly identified by dermoscopy

Advantages and Disadvantages

  • Valid indicators of diagnostic testThis glossary term has not yet been described. performance
  • Easily understood

The diagnosis made by dermoscopy has to be divided into two groups: benign and malignantThis glossary term has not yet been described.. This is surely an oversimplification of the diagnostic procedure of dermoscopy.

DermoscopyDermoscopy is a non invasive diagnostic method. is a tool to minimize uncertainty, thus aiming to the correct interpretation of a dermoscopic finding and leading to a decision of the necessity of further diagnostic procedures (excision). However, the interpretation of the dermoscopic findings is also influenced by other variables:

  • Clinical impression of the lesion
  • Ageprocess of becoming older of the patient
  • Anatomic side
  • Number and appearance of other lesions on the same patient

Other disadvantages to the evaluation of diagnostic tests by their sensitivity and specificity include the prevalence of the disease of interest (in this case melanomaThis glossary term has not yet been described.) not being taken into account, and the difficulties of comparing two diagnostic tests.

Diagnostic accuracy factors

The diagnostic accuracy of dermoscopy depends on many factors:

Level of training of dermatologists

The diagnostic accuracy of dermoscopy depends on the level of experience of the observer, as when applied by non experts is in fact worse than the diagnostic accuracy achieved without dermoscopy.[1] The diagnostic accuracy of primary care physicians simnifically improved after teaching of dermoscopy. [2]

Diagnostic difficulty of the evaluated lesions

There is overwhelming evidence confirming, that dermoscopy improves the diagnostic accuracy for melanoma in comparison to inspection with unaided eye.

Type of algorithmIn mathematics and computer science, an algorithm (Listeni/ˈælɡərɪðəm/ AL-gə-ri-dhəm) is a self-contained sequence of actions to be performed. Algorithms can perform calculation, data processing and automated reasoning tasks. used to evaluate the lesions

  • Pattern analysis[3]
  • ABCD rule[4]
  • SevenThis glossary term has not yet been described. pointThis glossary term has not yet been described. checklistThis glossary term has not yet been described.[5]
  • Menzies and associates algorithm[6]

A number of diagnostic algorithms have been developed for the dermoscopic evaluation of pigmented lesions. Pattern analysis has been shown to have a higher specificity than the other algorithms, but no significant differences were found with regard to sensitivity.[7]


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