Type
|
Purpose
|
When used
|
Examples/benefits and harms
|
Diagnostic testing
|
To provide definite diagnosis
|
In a patient with an existing condition
|
Turner syndrome 45,X |
Accurate diagnosis can lead to proper treatment |
Predictive testing
|
To provide risk assessment for presymptomatic states
|
Prenatal for reproductive choice decision |
Presymptomatic intervention may delay onset
|
For adult risk assessment |
Presymptomatic testing
|
To look for the presence of a gene mutation with complete penetrance, that is, having the mutation always leads to having the disease
|
In families with disease, for adults who choose to have testing after counseling
|
Huntington disease |
Finding of mutation may lead to prognostic information for individual affecting life planning; negative test may provide relief. Harms include worry, stigmatization, labeling; possible "survivor guilt" or ostracism if negative in family with others positive. |