ICD-10, which contains more than 70,000 diagnostic codes, replaced the ICD-9 code set, which relied on just 11,000 codes.

The grace period had only applied to claims submitted to Medicare and Medicaid, and while many commercial insurers offered similar flexibility, the majority did not, according to a report in Healthcare IT News.
The lead-up to the ICD-10 had many healthcare providers worried that the exponential increase in diagnostic codes would lead to more errors in medical claims, and ultimately denials, due to the new specificity required. But the years of lead-up to the launch due to a handful Congressional delays gave healthcare providers more time to prepare. The years of training, and the extra time to staff-up coding departments paid off. Most studies show the rate of denials had gone practically unchanged since the roll-out.

Though the grace period will end on Oct. 1, CMS said providers will still be allowed to use unspecified codes when they are warranted.

“While you should report specific diagnosis codes when they are supported by the available medical record documentation and clinical knowledge of the patient’s health condition, in some instances signs/symptoms or unspecified codes are the best choice to accurately reflect the health care encounter. You should code each healthcare encounter to the level of certainty known for that encounter.”