Medicare Compliance & Reimbursement

Caution: Lackluster sequencing can lead to claims denials.

Diagnosis coding can be complicated and confusing. Proper sequencing can help you fix issues and submit clean claims — as long as you do it correctly and consistently.

Sequencing requires a firm understanding of how to navigate the ICD-10 code book, said Sharon J. Oliver, CPC, CDEO, CPMA, CRC, AAPC Approved Instructor, coding consultant and owner of Medical Coding & Consultants in Jonesborough, Tennessee, at the beginning of her HEALTHCON Regional 2022 presentation “ICD-10-CM Sequencing: The Right Way.” Instructions are woven into several sections of the diagnosis code book, including general and chapter-specific guidelines.

If you’re like many coders and find sequencing intimidating and confusing, then the following tips were assembled just for you.

Understand the Etiology/Manifestation Rule

“One element of sequencing guidance that’s absolutely vital is abiding by the etiology/manifestation convention,” says Jan Blanchard, CPC, CPMA, consultant at Vermont-based PCC.

This is addressed in guideline 1.A.13. Basically stated, this ICD-10-CM guideline requires you to sequence the underlying condition first “if applicable, followed by the manifestation.” This refers to the ‘code first,’ ‘use additional code,’ and ‘in diseases classified elsewhere’ notes you see in the Tabular section of ICD-10. “‘Use additional’ is the requirement that the underlying condition be sequenced first followed by manifestation(s),” Blanchard adds.

Clinical examples: A familiar example in the sequencing rule can be found in the otitis media (H65-H67) codes. Here, you are required to use additional codes for such underlying conditions as exposure to environmental tobacco smoke (Z77.22 [Contact with and (suspected) exposure to environmental tobacco smoke (acute) (chronic)]), exposure to tobacco smoke in the perinatal period (P96.81 [Exposure to (parental) (environmental) tobacco smoke in the perinatal period]), and tobacco use (Z72.0 [Tobacco use]), among other underlying causes for Nonsuppurative otitis media (H65.- [Nonsuppurative otitis media]) and Suppurative and unspecified otitis media (H66.- [Suppurative and unspecified otitis media]) — if they are applicable.

Otitis media in diseases classified elsewhere codes (H67.- [Otitis media in diseases classified elsewhere]) can be both a manifestation and a primary condition. So, the codes carry instructions to code first the underlying diagnosis, such as plasminogen deficiency, coded to E88.02 (Plasminogen deficiency), or a viral disease not elsewhere classified (B00-B34). And, along with the Nonsuppurative otitis media codes, the H67.- codes can also be primary diagnoses with an associated condition such as a perforated tympanic membrane, coded to H72.- (Perforation of tympanic membrane).

Paint a Picture for the Payer

Clinically, of course, there are good reasons to follow the sequencing guidelines. “The code sequence paints a hierarchical picture of the patient’s condition, as the underlying causes and relationship(s) between diseases and symptoms are expressed by way of the codes’ place in the lineup,” Blanchard points out.

From a coding perspective, this also means listing the most specific diagnosis codes first. So, with our otitis media example, if a patient also complains of fever, you would list the H65-H67 code before R50.9 (Fever, unspecified) as the H65-H67 has the highest level of specificity.

But as is so often the case in medical coding, there are also financial stakes attached to the guidelines. “Correct sequencing avoids denials and sometimes assures maximum benefits for the patients. Although many diagnosis codes can be included on a claim, some payers will only look at the first diagnosis code or the first few listed diagnosis codes when assigning benefits,” notes JoAnne M. Wolf, RHIT, CPC, CEMC, coding manager at Children’s Health Network in Minneapolis.

This means sequencing “grows ever more important as more and more carriers assign complexity scores to patients covered by value-based care plans,” Blanchard concludes.

Use This Tip to Help Keep it All Straight

“Stick with the very basics of ICD-10 coding: index first, then tabular,” says Blanchard. “So long as you always consult the tabular section of your ICD-10 manual when using a new-to-you code, you’ll never wonder if you’re working with a code for which sequencing rules need to be applied. Make sure to review pairs of ‘Use additional code’ notes at the etiology code, and ‘Code first’ notes at the manifestation code to ensure proper sequencing order in the guidance,” Blanchard adds.

Expert tip: “Tab your copy of ICD-10 with reminders. Often, instructions appear in one place, but aren’t repeated by each code,” said Oliver. “Everything needs to be read together. There is no such thing as remembering everything and knowing what to code without looking at the notes and the guidelines,” Oliver continued.