It is a client problem that is present at the time of the nursing assessment. Examples are Ineffective Breathing Pattern and Anxiety. An actual nursing diagnosis is based on the presence of associated signs and symptoms.
RISK NURSING DIAGNOSIS
It is a clinical judgment that a problem does not exist, but the presence of risk factors indicates that a problem is likely to develop unless nurses intervene. For example, all people admitted to a hospital have some possibility of acquiring an infection; however, a client with diabetes or a compromised immune system is at higher risk than others. Therefore, the nurse would appropriately use the label Risk for Infection to describe the client’s health status.
“Describes human responses to levels of wellness in an individual, family or community that have a readiness for enhancement.” Examples of wellness diagnosis would be Readiness for Enhanced spiritual Well Being or Readiness for Enhanced Family Coping.
POSSIBLE NURSING DIAGNOSIS
It is one in which evidence about a health problem is incomplete or unclear. A possible diagnosis requires more data either to support or to refute it. For example, an elderly widow who lives alone is admitted to the hospital. The nurse notices that she has no visitors and is pleased with attention and conversation from the nursing staff. Until more data are collected, the nurse may write a nursing diagnosis of Possible Social Isolation related to unknown etiology.
It is a diagnosis that is associated with a cluster of other diagnoses.
Source : http://www.nursing-nurse.com