A diagnosis of OCPD is only received when four out of the eight criteria are met.The eight criteria of OCPD described in the DSM-5 (of which four are required to be present in a patient for a diagnosis) are:

Preoccupation with details
Perfectionism interfering with task completion
Rigidity and stubbornness
Reluctance to delegate
Excessive conscientiousness and pedantry (excessive concern with minor details and rules)
Workaholic behavior
Miserliness (excessive desire to save money)
Unable to discard worn-out or worthless objectsThe list of criteria for the ICD-10 is similar, but does not include the last three criteria in the above list, and additionally includes the symptoms "intrusive thoughts" and "excessive doubt and caution" as criteria for diagnosis. Alternative model for diagnosis
The DSM-5 also includes an alternative set of diagnostic criteria as per the dimensional model of conceptualizing personality disorders. Under the proposed set of criteria, a person only receives a diagnosis when there is an impairment in two out of four areas of ones personality functioning, and when there are three out of four pathological traits, one of which must be rigid perfectionism. The patient must also meet the general criteria C through G for a personality disorder, which state that the traits and symptoms being displayed by the patient must be stable and unchanging over time with an onset of at least adolescence or early adulthood, visible in a variety of situations, not caused by another mental disorder, not caused by a substance or medical condition, and abnormal in comparison to a persons developmental stage and culture/religion.
Only when these traits become extreme, maladaptive, and cause clinically significant impairment in several aspects of ones life should a diagnosis of OCPD be considered. Personality change due to another medical condition. Obsessive–compulsive personality disorder must be differentiated from a personality change due to a medical condition, which affects the central nervous system, and may cause changes in behavior and traits. Substance use disorders. Substance use may cause the advent of obsessive-compulsive traits. It is necessary that this is distinguished from underlying and persistent behavior, which must occur when a person is not under influence of a substance. ICD-10
The World Health Organizations ICD-10 uses the term anankastic personality disorder (F60.5). At least four of the following must be present:

Feelings of doubt
Perfectionism
Excessive conscientiousness
Checking and preoccupation with details
Stubbornness
Caution
Rigidity
Insistent and unwelcome thoughts or impulses that do not attain the severity of an obsessive-compulsive disorder. Millons subtypes
In his book, Personality Disorders in Modern Life, Theodore Millon describes 5 types of obsessive–compulsive personality disorder, which he shortened to compulsive personality disorder. Comorbidity
Obsessive–compulsive disorder
OCPD is often confused with obsessive-compulsive disorder (OCD). Despite the similar names, they are two distinct disorders. Some OCPD individuals do have OCD, and the two can be found in the same family, sometimes along with eating disorders.The rate of comorbidity of OCPD in patients with OCD is estimated to be around 15–28%.