Not Otherwise Specified

In medicine, Not Otherwise Specified (NOS) is a subcategory in systems of disease/disorder classification such as ICD-9, ICD-10, or DSM-IV. It is generally used to note the presence of an illness where the symptoms presented were sufficient to make a general diagnosis, but where a specific diagnosis was not made. The DSM-IV, for example, "applies the term not otherwise specified (NOS) to a disorder or disturbance that does not meet the criteria for the specific disorders already discussed".Patricia G. O'Brien, Winifred Z. Kennedy, M.S.N., R.N., Karen A Ballard, M.A., R.N., ''Psychiatric Mental Health Nursing'' (2012), p. 501. The term was introduced because "it is sometimes impossible for the practitioner completing the diagnostic assessment to categorize all the symptoms that a client is experiencing into one diagnostic category".Sophia F. Dziegielewski, ''DSM-IV-TR in Action'' (2013), p. 50-51. In the context of mental health diagnoses, four situations have been outlined for which such a diagnosis may be considered appropriate:

It is noted, however, that the use of an NOS classification invites scrutiny when billing or seeking reimbursement for practitioners.

Examples

This classification is commonly used in psychiatric diagnoses, such as in:
* DD-NOS, depressive disorder
* ED-NOS, eating disorder
* MD-NOS, mood disorder
* PD-NOS, personality disorder
* PDD-NOS, pervasive developmental disorder
* Psychotic disorder not otherwise specified

It is also used in the conditions:
* PTCL-NOS, peripheral T-cell lymphoma not otherwise specified
* Adenocarcinoma not otherwise specified

The ICD-10 also uses this phrase for various things, such as:
* Fall from, out of or through building, not otherwise specified (W13.9)

The phrase is also used within the List of UN numbers, where it refers to a generic entry, e.g. "UN 1993: Flammable liquid, N.O.S.".

References

{{reflist

International Classification of Diseases
Medical terminology