ICD-10: 26 Tips You Absolutely Want to Know!

Betsy Nicoletti, MS


September 23, 2015

In This Article

New Factors to Be Aware of

Perinatal Coding

Codes for newborn conditions are in Chapter 16, "Certain conditions originating in the perinatal period," and conveniently start with the letter P.

Healthy newborns are coded from the final chapter in ICD-10. These perinatal codes are for use on newborn records and are never used on the mother's chart. Use these codes when the maternal condition is specified as the cause (confirmed or suspected) of potential morbidity to the baby, which has its origin in the perinatal period. These codes can also be used when a newborn is suspected of having a condition such as an infection, but it is later found not to exist.

Use codes in this chapter for conditions originating in the perinatal period.


In the hospital setting, there are rules about "querying" a physician for additional documentation in selecting diagnosis codes. Diagnosis code selection drives the payment amount that a hospital receives for inpatient Medicare stays.

On the physician side, payment is driven by CPT code. When coders ask the physician to clarify a diagnosis code, it usually doesn't change the amount the practice will be paid. It may, however, change whether or not the practice does get paid. Coders and billers have twin goals when they ask the clinician for clarification: They want to prevent denials by submitting clean claims, and they want to select an accurate diagnosis code based not on coverage but on the patient's clinical conditions.

Asking for clarification before claims submission can prevent denials.

Risk-Adjusted Diagnosis Coding

Or the answer to the question: "Who cares? This level of specificity doesn't change how I treat the patient."

Physicians are understandably unhappy about the expansion of diagnosis coding. Using an electronic health record, most healthcare professionals themselves select the diagnosis code. Searching through the ICD-10 code set in a small pop-up box doesn't seem like a good use of clinical time.

However, practices that are or will be part of an accountable care organization or alternative payment model or who have risk-adjusted contracts with private payers will find that part of their reimbursement is based on the level of severity of patients they treat. Reporting conditions with manifestations (bleeding, psychosis, diarrhea) and reporting patients' underlying comorbid conditions are critical as we change reimbursement models.

Document comorbidities and use codes that describe manifestations or symptoms of a condition.


Along with the common seventh character extenders A and D, there is a seventh character extender used on injury and poisoning codes for the sequela of an injury. This seventh character S, for sequela, is described in ICD-10 as for use "for complications or conditions that arise as a direct result of the condition such as a scar forming after a burn." This seventh character extender is used only to describe the long-term after-effects of an injury or poisoning.

Aftercare codes from the last chapter (which begin with the letter Z) are not used to describe the aftercare injuries or poisonings. Report the code for the initial injury, changing the seventh character to S. Also report the symptom or sequela, such as the scar or limping or pain. That sequela is reported in the first position.

For conditions arising after an injury, use the seventh character S.

Table of Drugs and Chemicals

The table of drugs and chemicals has new headings for poisoning and a new column and concept of underdosing. Start in the table located in the index and then select a code from the tabular list. These codes are in Chapter 19, the injury chapter, and will require a seventh character extender of A (initial), D (subsequent), or S (sequela).

Underdosing is used when the patient hasn't taken the medication as ordered. Code first the condition that was affected by the underdosing, and code second the code for underdosing. The adverse effect code is used when the patient took the medicine as prescribed and had a side effect or reaction such as nausea while taking erythromycin. In this case, code first the adverse effect (the nausea) and code second the adverse effect code—T36.3X5A Adverse effect of macrolides, initial encounter. If the patient has taken the wrong medicine or a medication that wasn't prescribed for them, use the poisoning accidental code and assign it as the first code.

Reactions to drugs and chemicals are trauma codes and need a seventh character extender.


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