Medical coding is a critical component of the healthcare industry, providing a standardized system for classifying diseases, diagnoses, and medical procedures. The adoption of the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) has brought significant changes to medical coders. Whether you are new to coding or an experienced professional, mastering the rules of the road for ICD-10-CM is essential for accurate and efficient coding. Sometimes, new coding professionals receive on-the-job training and aren't given the time to study the guidelines. And more experienced coding professionals sometimes fall into the trap of “I know how to code for XYZ” and don't study the updates when they come out. The last article highlighted the general ICD-10-CM coding guidelines. This article continues the discussion, moving on to Chapter 1: Certain Infectious and Parasitic Diseases (A00-B99), U07.1, and U09.9, and discusses some of the major guidelines.
Structure of Chapter 1: ICD-10-CM
Chapter 1 of the ICD-10-CM is dedicated to coding infectious and parasitic diseases, encompassing a wide range of conditions caused by bacteria, viruses, fungi, and parasites. The codes in this chapter are organized into various blocks, each representing a specific group of diseases.
Here's a breakdown of the major blocks within Chapter 1:
- A00-A09: Intestinal infectious diseases
- A15-A19: Tuberculosis
- A20-A28: Certain zoonotic bacterial diseases
- A30-A49: Other bacterial diseases
- A50-A64: Infections with a predominantly sexual mode of transmission
- A65-A69: Other spirochetal diseases
- A70-A74: Other diseases caused by chlamydiae
- A75-A79: Rickettsioses
- A80-A89: Viral and prion infections of the central nervous system
- A90-A99: Arthropod-borne viral fevers and viral hemorrhagic fevers
- B00-B09: Viral infections characterized by skin and mucous membrane lesions
- B10-B19: Viral hepatitis
- B20-B24: Human immunodeficiency virus (HIV) disease
- B25-B34: Other viral diseases
- B35-B49: Mycoses
- B50-B64: Protozoal diseases
- B65-B83: Helminthiases
- B85-B89: Pediculosis, acariasis, and other infestations
- B90-B94: Sequelae of infectious and parasitic diseases
- B95-B97: Bacterial and viral infectious agents
- B99: Other infectious diseases
Specific Guidelines for Key Diseases
Human Immunodeficiency Virus (HIV) Infections
Code only confirmed cases of HIV infection/illness. The provider's diagnostic statement is sufficient.
Selection and Sequencing of HIV Codes:
- Patient admitted for HIV-related condition: Use B20 as the principal diagnosis, followed by codes for all reported HIV-related conditions.
- Patient with HIV admitted for unrelated condition: Code the unrelated condition first, followed by B20 and additional HIV-related conditions.
- Asymptomatic HIV: Use Z21 for patients listed as “HIV positive” without symptoms or HIV-related illnesses.
- Inconclusive HIV Serology: Use R75 for patients with inconclusive HIV serology without a definitive diagnosis.
- Previously Diagnosed HIV-Related Illness: Use B20 for any known prior diagnosis of an HIV-related illness.
- HIV in Pregnancy, Childbirth, and the Puerperium: Use O98.7- followed by B20 and codes for the HIV-related illnesses for symptomatic patients. For asymptomatic patients, use O98.7- and Z21.
- Encounters for HIV Testing: Use Z11.4 for screening and Z71.7 for HIV counseling if provided. Code signs and symptoms if present.
- HIV Managed by Antiretroviral Medication: Use B20 and Z79.899 for long-term antiretroviral therapy.
- Encounter for HIV Prophylaxis: Use Z29.81 for pre-exposure prophylaxis (PrEP).
Examples:
- A patient with HIV presents with Kaposi's sarcoma of the skin. The correct codes are B20 (HIV disease) and C46.0 (Kaposi's sarcoma of skin). The B20 code would be first-listed, followed by the HIV-related condition according to the guidelines.
- A patient with diabetes mellitus type II is seen for a routine follow-up visit. His diabetes is well-controlled with medication. It is also noted that the patient has AIDS. The appropriate codes are E.11.9 (type II diabetes mellitus without complications) and B20 (HIV disease). In this scenario, the B20 code is listed second as diabetes is not an HIV-related condition.
Sepsis Infections
Sepsis and severe sepsis have separate codes:
- Sepsis: Sepsis is coded with a single code from category A41 (Other sepsis) unless the sepsis is specified as due to a specific organism, in which case a combination code for the specific infection should be used.
Example: A patient diagnosed with sepsis due to Staphylococcus aureus should be coded as A41.01 (Sepsis due to Methicillin susceptible Staphylococcus aureus).
- Severe Sepsis: Severe sepsis is coded with a combination of codes: one for the underlying systemic infection and another for the severe sepsis itself, along with any associated acute organ dysfunction. Use code R65.20 (Severe sepsis without septic shock) or R65.21 (Severe sepsis with septic shock) to indicate severe sepsis.
Example: A patient diagnosed with severe sepsis with acute kidney failure should be coded as A41.9 (Sepsis, unspecified organism) and R65.20 (Severe sepsis without septic shock), along with N17.9 (Acute kidney failure, unspecified).
When sepsis results from a postprocedural infection, a combination of codes should be used:
- One for the specific type of infection
- Another for the sepsis
Example: A patient develops sepsis after a surgical procedure due to a postoperative infection. The correct codes would be T81.40XA (Infection following a procedure, initial encounter) and A41.9 (Sepsis, unspecified organism).
If sepsis is due to a non-infectious process, the code for the non-infectious condition is:
- Sequenced first
- Followed by the appropriate sepsis code
Example: A patient develops sepsis due to an 8% total body surface area (TBSA) burn injury. The correct codes would be the code for the specific burn injury (e.g., T31.0 for burns involving less than 10% of body surface) followed by A41.9 (Sepsis, unspecified organism).
Special considerations of sepsis include:
- Coding for Sepsis in Newborns: Sepsis in newborns is coded differently and requires codes from category P36 (Bacterial sepsis of newborn).
Example: A newborn diagnosed with neonatal sepsis due to E. coli should be coded as P36.4 (Sepsis of newborn due to Escherichia coli [E. coli]).
- Sepsis and Septic Shock: Septic shock is a severe and potentially fatal condition that can result from sepsis. It is coded using a combination of codes for the underlying sepsis and the septic shock.
Example: A patient diagnosed with sepsis and septic shock due to Streptococcus pneumoniae should be coded as A40.3 (Sepsis due to Streptococcus pneumoniae) and R65.21 (Severe sepsis with septic shock).
Coronavirus Infections
COVID-19:
- ICD-10-CM Code: U07.1 (COVID-19)
- Confirmed Only: This code is used for confirmed cases of COVID-19. A confirmed diagnosis does not require a positive test result; a provider's diagnostic statement that the patient has COVID-19 is sufficient.
Example: A patient is admitted with a confirmed diagnosis of COVID-19. The correct code is U07.1.
Encounters for Screening:
- ICD-10-CM Code: Z11.52 (Encounter for screening for COVID-19)
- Screening Only: Use this code when a patient is being screened for COVID-19 and does not exhibit symptoms or have a known exposure to the virus.
Example: A patient comes in for a routine COVID-19 screening required by their workplace. The correct code is Z11.52.
Exposure to COVID-19:
- ICD-10-CM Code: Z20.822 (Contact with and [suspected] exposure to COVID-19)
- Suspected Only: Use this code when a patient is exposed to COVID-19 and is either asymptomatic or is being tested for COVID-19 but has not yet been confirmed to have the disease.
Example: A patient reports close contact with a confirmed COVID-19 case and is being tested for the virus. The correct code is Z20.8 2 2
COVID-19 in Pregnancy, Childbirth, and the Puerperium:
- ICD-10-CM Codes: O98.5- (Other viral diseases complicating pregnancy, childbirth, and the puerperium)
- Pregnancy/Childbirth/Puerperium Only: When COVID-19 complicates pregnancy, childbirth, or the puerperium, use codes from category O98.5- along with U07.1.
Example: A pregnant patient in her second trimester is diagnosed with COVID-19. The correct codes are O98.512 and U07.1.
Multisystem Inflammatory Syndrome (MIS):
- ICD-10-CM Code: M35.81 (Multisystem inflammatory syndrome)
- In Addition-To: MIS is a condition that can occur after a COVID-19 infection. Use this code for patients diagnosed with this syndrome, and U07.1 if COVID-19 is still present.
Example: A child is diagnosed with multisystem inflammatory syndrome following a COVID-19 infection. The correct codes are M35.81 and U07.1 if the COVID-19 infection is still active. If COVID is still present, U07.1 would be coded first according to the guidelines.
Post-COVID-19 Condition:
- ICD-10-CM Code: U09.9 (Post COVID-19 condition, unspecified)
- Post Only: This code is used for conditions that develop as a result of a previous COVID-19 infection. Do not use U09.9 during an active COVID-19 infection.
Example: A patient presents with fatigue and dyspnea months after recovering from COVID-19. The correct code is U09.9 for the post-COVID-19 condition, along with additional codes for the specific symptoms. U09.9 would be coded following the specific condition related to COVID-19, if known.
Special Considerations:
- Asymptomatic COVID-19: When a patient tests positive for COVID-19 but is asymptomatic, the code U07.1 should still be used.
Example: A patient tests positive for COVID-19 but does not exhibit any symptoms. The correct code is U07.1.
- Symptoms without a Confirmed Diagnosis: When a patient presents with symptoms of COVID-19 but no confirmed diagnosis, code the symptoms.
Example: A patient presents with fever, cough, and shortness of breath but has not been confirmed to have COVID-19. The correct codes are R50.9 (Fever, unspecified), R05 (Cough), and R06.02 (Shortness of breath).
Conclusion
Accurate coding of ICD-10-CM is crucial for patient care, epidemiological tracking, and reimbursement. By adhering to the official guidelines and ensuring thorough documentation, medical coding professionals can contribute to effective management and reporting of cases. Continuous education and staying updated with evolving guidelines are essential for mastering the complexities of coding. In future issues, watch for these articles on other specific chapters of ICD-10-CM.
Betty Hovey, CCS-P, CDIP, CPC, COC, CPMA, CPCD, CPB, CPC-I, is the Senior Consultant/Owner of Compliant Health Care Solutions, a medical consulting firm that provides compliant solutions to issues for all types of healthcare entities. Chcs.consulting