1. Certain Infectious and Parasitic Diseases (A00-B99)
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

2. Includes: diseases generally recognized as communicable or transmissible
Use additional code to identify resistance to antimicrobial drugs (Z16)
New section called infections with predominantly sexual mode of transmission (A50-A64)
New sections for Viral Hepatitis (B15-B19) and Other Viral Disease (B25-B34)

3. Changes in Chapter 1 Septicemia has been replaced with the term sepsis
Severe Sepsis is the term in ICD-10 that is used for SIRS due to an infectious process
Sepsis due to Streptococcus (streptococcal Septicemia) – documentation must specify due to Group A, Group B, or Streptococcus Pneumoniae
Streptococcal sore throat has been moved to the respiratory chapter

4. Chapter 1
When coding sepsis or AIDS, it is important to review the Coding Guidelines and the notes at the category level of ICD-10-CM
Categories B90-B94 are to be used to indicate conditions in categories A00-B89 as the cause of sequelae, which are themselves classified elsewhere.

5. I.C.1.a.1. HIV Infections Code Only Confirmed Cases
Code only confirmed cases of HIV
“Confirmation” does not require documentation of positive serology, the provider’s diagnostic statement that the patient is HIV positive is sufficient
Asymptomatic HIV-Z21 is to be applied when the patient without documentation of symptoms is listed as being “HIV Positive”. Do not use this code if the terms AIDS is used or if the patient is treated for any HIV-related illness.

6. I.C.1.a.2. HIV - Selection and Sequencing of HIV Codes
(a) Patient admitted for HIV-related condition
If a patient is admitted for an HIV-related condition, the principal diagnosis should be B20, Human immunodeficiency virus [HIV] disease followed by additional diagnosis codes for all reported HIV-related conditions.
(b) Patient with HIV disease admitted for unrelated condition
If a patient with HIV disease is admitted for an unrelated condition, the code for the unrelated condition should be the principal diagnosis. Other diagnoses would be B20 followed by additional diagnosis codes for all reported HIV-related conditions.
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

7. I.C.1.a.2. HIV - Selection and Sequencing of HIV Codes -2
(c) Whether the patient is newly diagnosed
Whether the patient is newly diagnosed or has had previous admissions/encounters for HIV conditions is irrelevant to the sequencing decision.
(d) Asymptomatic human immunodeficiency virus
Z21, Asymptomatic human immunodeficiency virus [HIV] infection status, is applied when the patient without any documentation of symptoms is listed “HIV positive,” “known HIV,” “HIV test positive”. Do not use this code if the term “AIDS” is used or if the patient is treated for any HIV-related illness or is described as having any condition(s) resulting from his/her HIV positive status; use B20 in these cases.
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

8. I.C.1.a.2. HIV - Selection and Sequencing of HIV Codes -3
(e) Patients with inconclusive HIV serology
Patients with inconclusive HIV serology, but no definitive diagnosis or manifestations of the illness, may be assigned code R75, Inconclusive laboratory evidence of human immunodeficiency virus [HIV].
(f) Previously diagnosed HIV-related illness
Patients with any known prior diagnosis of an HIV-related illness should be coded to B20. Once a patient develops an HIV-related illness, the patient should always be assigned code B20. Patients previously diagnosed with any HIV illness (B20) should never be assigned to R75 or Z21, Asymptomatic human immunodeficiency virus [HIV] infection status.
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

9. I.C.1.b. Infectious Agents
Certain infections are classified in chapters other than Chapter 1 and no organism is identified as part of the infection code
An additional code from Chapter 1 should be used to identify the organism:
B95 Streptococcus, Staphylococcus, and Enterococcus
B96, Other bacterial agents
B97 Viral agents

10. I.C.1.b. Infectious Agents -2
An instructional note will be found at the infection code advising that an additional organism code is required
Use an additional code
(B95 – B97) to identify
infectious agent

11. I.C.1.b. Infectious Agents -3
Code first condition resulting from (sequela) the infectious or parasitic disease
Bacterial and viral infectious agents (B95-B97) are provided for use as supplementary or additional codes to identify the infectious agent(s) in diseases classified elsewhere
Index
Infection, infected, infective; bacterial as cause of disease classified elsewhere; Streptococcus group A – B95.5
Streptococcus, streptococcal; group A, as cause of disease classified elsewhere – B95.5

12. Examples UTI with hematuria due to E.coli
N30.91, Cystitis unspecified with hematuria
B96.2, Escherichia coli [E. coli] as the cause of diseases classified elsewhere
Pneumonia due to streptococcus group B with sepsis
J15.3, Pneumonia due to streptococcus, group B
A41.9 Sepsis, unspecified organism Septicemia NOS

13. Chapter 1 Coding Case #1
This 80-year-old female patient was seen with fever, malaise, and left flank pain. A urinalysis was performed and showed bacteria more than 100,000/ml. This was followed by a culture, showing E. coli growth as the cause of the UTI. What diagnosis codes are assigned?

14. Answer #1
Rationale: The symptoms associated with the UTI should not be coded. The “use additional code” note under N39.0 instructs the coder to an additional code (B95-B97) to identify the infectious agent.
N39.0
Infection, infected, infective (opportunistic), urinary (tract)
B96.20
Infection, infected, infective opportunistic), bacterial NOS, as cause of disease classified elsewhere, Escherichia coli [E. coli] (see also Escherichia coli)

15. I.C.1.c. Infections Resistant to Antibiotics
Identify all infections documented as antibiotic resistant
Assign code Z16
Infection with drug-resistant microorganisms following the infection code

16. Coding Note: ICD-10-CM has created a range of
codes to identify infections with a predominantly sexual mode of transmission (A50-A64). It is important to note that human immunodeficiency virus (HIV) disease is excluded from this range of codes.

17. I.C.1.d. Sepsis, Severe Sepsis, and Septic Shock
Coding of (a) Sepsis
Assign the appropriate code for the underlying systemic infection. Use A41.9 for unspecified organism
R65.2, Severe sepsis, should not be assigned unless severe sepsis or acute organ dysfunction is documented

18. Exercise #1
This 87-year-old nursing home patient is being treated with IV antibiotics for E. coli sepsis. What diagnosis codes are assigned?

19. Answer #1
Rationale: Without documentation of severe sepsis or an associated organ dysfunction, only one code from category A41 is necessary for correct code assignment.
A41.51
Sepsis (generalized), Escherichia coli (E. Coli). Review Tabular for complete code assignment.

20. meaning urinary tract infection 599.0 Urosepsis – code to condition
Urosepsis Guidelines
Urosepsis cannot be coded in ICD-10-CM Guideline states: “The term urosepsis is a nonspecific term. It is not to be considered synonymous with sepsis. It has no default code in the Alphabetic Index. Should a provider use this term, he/she must be queried for clarification.”
ICD-9-CM Alpha Index
Urosepsis
meaning sepsis
meaning urinary tract infection 599.0
ICD-10-CM Alpha Index
Urosepsis – code to condition

21. I.C.1.d. Sepsis, Severe Sepsis, and Septic Shock -2
Coding of (b) Severe Sepsis
Requires at least two codes:
1st underlying systemic infection
2nd code from subcategory R65.2 for severe sepsis
If the causal organism is not document, assign A41.9, Sepsis unspecified
Assign additional codes for the associated acute organ dysfunction

22. I.C.1.d.2. Septic Shock Instructors Manual page 106
Student Manual page 95
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

23. Exercise #1
This 25-year-old woman was transferred from an outside facility for treatment of septic shock and acute meningococcal sepsis. The outside facility was unable to manage her severe illness. What diagnosis codes are assigned?
Coding Guideline I.C.1.d.2. Septic Shock
Septic shock generally refers to circulatory failure associated with severe sepsis and, therefore, it represents a type of acute organ dysfunction.
For cases of septic shock, the code for the systemic infection should be sequenced first,
followed by code R65.21, Severe sepsis with septic shock or code T81.12, Postprocedural
septic shock. Any additional codes for the other acute organ dysfunctions should also be
assigned. As noted in the sequencing instructions in the Tabular List, the code for septic shock cannot be assigned as a principal diagnosis.
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

24. Answer #1
Rationale: The combination code of severe sepsis with septic shock is assigned as a secondary diagnosis although severe sepsis is not.
A39.2
Sepsis (generalized), meningococcal, acute
R65.21
Shock, septic (due to severe sepsis)

25. d. Sepsis, Severe Sepsis, and Septic Shock
3. Sequencing of Severe Sepsis
If severe sepsis is present on admission, and meets the definition of principal diagnosis, the underlying systemic infection should be assigned as principal diagnosis followed by the appropriate code from subcategory R65.2 as required by the sequencing rules in the Tabular List. A code from subcategory R65.2 can never be assigned as a principal diagnosis.
When severe sepsis develops during an encounter (it was not present on admission) the underlying systemic infection and the appropriate code from subcategory R65.2 should be assigned as secondary diagnoses.

26. d. Sepsis, Severe Sepsis, and Septic Shock -2
4. Sepsis and severe sepsis with localized infection
If the reason for admission is both sepsis or severe sepsis and a localized infection, such as pneumonia or cellulitis, a code(s) for the underlying systemic infection should be assigned first and the code for the localized infection should be assigned as a secondary diagnosis.

27. Severe Sepsis Coding Example
ICD-9-CM
Severe sepsis due to hemophilus influenza with septic shock and acute renal failure
(Hemophilus influenza septicemia)
(Severe sepsis)
(Septic shock)
584.9 (Acute renal failure)
ICD-10-CM
A41.3 (Hemophilus influenza sepsis)
R65.21 (Severe sepsis with septic shock)
N17.9 (Acute renal failure)

28. d. Sepsis, Severe Sepsis, and Septic Shock -3
5. Sepsis due to a postprocedural infection
(a) Documentation of Causal relationship – As with all postprocedural complications, code assignment is based on the provider’s documentation of the relationship between the infection and the procedure.
(b) Sepsis due to a postprocedural infection – The postprocedural infection code (such as T80.2, Infections following infusion, transfusion and therapeutic injection, or T81.4, Infection following a procedure) should be coded first, followed by the code for the specific infection. If severe sepsis is documented, the appropriate code from subcategory R should also be assigned with the additional code(s) for any acute organ dysfunction.

29. d. Sepsis, Severe Sepsis, and Septic Shock -4
5. Sepsis due to a postprocedural infection
(c) Postprocedural infection and postprocedural septic shock – In cases where a postprocedural infection has occurred and has resulted in severe sepsis and postprocedural septic shock, the code for the precipitating complication such as code T81.4, Infection following a procedure or O86.0, Infection of obstetrical surgical wound should be coded first followed by code R65.21, Severe sepsis with septic shock and a code for the systemic infection.

30. d. Sepsis, Severe Sepsis, and Septic Shock -5
6. Sepsis and severe sepsis associated with noninfectious process (condition)
If sepsis or severe sepsis is documented as associated with a noninfectious condition, such as a burn or serious injury, the code for the noninfectious condition should be sequenced first, followed by the code for the resulting infection
If the infection meets the definition of principal diagnosis it should be sequenced before the noninfectious condition.
Only one code from category R65 should be assigned. Therefore, when a non-infectious condition leads to an infection resulting in severe sepsis, assign the appropriate code from subcategory R65.2, Severe sepsis. Do not additionally assign a code from subcategory R65.1 SIRS of noninfectious origin.

31. Coding Note: In ICD-10-CM, when coding an infection due to an indwelling urinary catheter, the coding professional is instructed to use an additional code to identify the infection. Additionally, if the infectious agent is also known, this should be assigned as an additional diagnosis.

32. e. Methicillin Resistant Staphylococcus Aureus (MRSA) Conditions
1. Selection and sequencing of MRSA codes
(a) Combination codes for MRSA infection – When an infection due to MRSA has a combination code that includes the causal organism assign the appropriate combination code
Do not code B95.62 MRSA infection as the cause of diseases elsewhere or Z16.11 Resistance to penicillin as additional codes
(b) Other codes for MRSA infection- When there is a current infection and that infection does not have a combination code that includes the causal organism, assign the appropriate code to identify the condition along with code B95.62
Do not also assign Z16.11, Resistance to penicillin

33. e. Methicillin Resistant Staphylococcus Aureus (MRSA) Conditions -2
1. Selection and sequencing of MRSA codes
c) Methicillin susceptible Staphylococcus aureus (MSSA) and MRSA colonization- means that MSSA or MSRA is present on or in the body without necessarily causing illness.
Assign code Z22.322, Carrier or suspected carrier of MRSA or Z22.321, Carrier or suspected carrier of MSSA

34. Chapter 1: Certain Infectious and Parasitic Diseases
Q&A
Chapter 1: Certain Infectious and Parasitic Diseases

35. Exercise #1
True or false? In ICD-10-CM, code B20 is used to report a diagnosis of symptomatic HIV disease.
a. True
b. False
Instructors Manual page 41
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

36. Answer #1
Answer: a. True
Rationale: Code B20, Human immunodeficiency virus disease, is used to report a diagnosis of symptomatic HIV disease. Code Z21, Asymptomatic human immunodeficiency virus infection is used to report a patient who has tested HIV positive but has not yet developed symptoms from the HIV disease.
Instructors Manual page 41
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

37. Exercise #2
True or false? Bacteremia and septicemia NOS are coded to R65.2.
a. True
b. False
Instructors Manual page 41
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

38. Answer #2 Answer: b. False
Rationale: Bacteremia is coded to R78.81 and septicemia to A41.9. A code from subcategory R should not be assigned unless severe sepsis or an associated acute organ dysfunction is documented.
Instructors Manual page 41
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

39. Exercise #3
A patient with a diagnosis of interstitial cystitis due to E. coli with hematuria is coded:
a. N30.11, N02.9
b. N30.10, N02.9, B96.20
c. N30.11, B96.20
d. N30.91, B96.20
Instructors Manual page 83
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

40. Answer #3
Answer: c. N30.11, B96.20
Rationale: The code for interstitial cystitis is N30.11 and the code for the E. coli is B A note appears in the Tabular under N30 that instructs the coding professional to use an additional code to identify infectious agent (B95-B97).
Instructors Manual page 83
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

41. Exercise #4
True or false? When assigning the principal diagnosis for a patient with AIDS, the AIDS code would always be sequenced before any other conditions.
Instructors Manual page 92
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

42. Answer #4
Answer: False
Rationale: When a patient is admitted with an HIV- related condition, the principal diagnosis should be B20, Human immunodeficiency virus [HIV] disease, followed by additional diagnosis codes for all reported HIV-related conditions (ICD-10-CM Coding Guideline I.C.1.a.2.a). When a patient with HIV disease is admitted for an unrelated condition, for example, trauma, the code for the unrelated condition should be the principal diagnosis with B20 listed as an additional code (ICD-10-CM Coding Guideline I.C.1.a.2.b).
Instructors Manual page 92
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

43. Exercise #5
True or False? Patients with a prior diagnosis of an HIV-related illness should be assigned the code for AIDS (B20) on every subsequent admission.
Instructors Manual page 94
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

44. Answer #5
Answer: True
Rationale: Patients with any known prior diagnosis of an HIV-related illness should be coded to B20. Once a patient has developed an HIV-related illness, the patient should always be assigned code B20 on every subsequent admission or encounter. Patients previously diagnosed with any HIV illness (B20) should never be assigned to R75 or Z21, Asymptomatic human immunodeficiency virus [HIV] infection status (ICD-10-CM Coding Guideline I.C.1.a.2.f).
Instructors Manual page 94
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

45. Exercise #6
True or false? When coding severe sepsis, a minimum of three codes is required.
Instructors Manual page 97
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic

46. Answer #6
Answer: False
Rationale: The coding of severe sepsis requires a minimum of two codes: first a code for the underlying systemic infection, followed by a code from subcategory R65.2, Severe sepsis. If the causal organism is not documented, assign code A41.9, Sepsis, unspecified organism, for the infection (ICD-10-CM Coding Guideline I.C.1.d.1.b). Additional codes for the other acute organ dysfunctions should also be assigned. This condition usually will result in a total of three codes, except in the case of combination codes, such as severe sepsis with septic shock.
Instructors Manual page 97
ICD-10 Sect IC Chap 1 Certain Infections & Parasitic