Skip to main content

P35-P39 vs Z21

P35-P39 (Infections specific to the perinatal period (P35-P39)) compared with Z21 (Asymptomatic human immunodeficiency virus [HIV] infection status), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because P35-P39 lists Z21 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named, billing status and chapter.P35-P39 is “Infections specific to the perinatal period (P35-P39)”; Z21 is “Asymptomatic human immunodeficiency virus [HIV] infection status”. P35-P39 is a non-billable header; Z21 is billable. P35-P39 sits in P00-P96 — Certain Conditions Originating in the Perinatal Period (P00-P96); Z21 in Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99).

Registry fact

Can these codes be reported together?

Yes, when both are documented.P35-P39 lists Z21 under Excludes2: “asymptomatic human immunodeficiency virus [HIV] infection status (Z21)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. Z21 carries 5 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.P35-P39’s tabular entry: “asymptomatic human immunodeficiency virus [HIV] infection status (Z21)”. The note covers Z21.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

One is a header.P35-P39 is a non-billable header, but Z21 is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

P35-P39
Infections specific to the perinatal period (P35-P39)
↔
Z21
Asymptomatic human immunodeficiency virus [HIV] infection status

What we found

Yes, when both are documented.P35-P39 carries an Excludes2 note covering Z21: “asymptomatic human immunodeficiency virus [HIV] infection status (Z21)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
P35-P39

Infections specific to the perinatal period (P35-P39)

Z21

Asymptomatic human immunodeficiency virus [HIV] infection status

StatusDiffers
P35-P39
Non-billable header

A header is not reported on a claim; a code beneath it is.

Z21
Billable
Excludes1Differs
P35-P39

None at this code

Z21
  • acquired immunodeficiency syndrome (B20)
  • contact with human immunodeficiency virus [HIV] (Z20.6)
  • exposure to human immunodeficiency virus [HIV] (Z20.6)
  • human immunodeficiency virus [HIV] disease (B20)
  • inconclusive laboratory evidence of human immunodeficiency virus [HIV] (R75)
Excludes2Differs
P35-P39
  • asymptomatic human immunodeficiency virus [HIV] infection status (Z21)
  • congenital gonococcal infection (A54.-)
  • congenital pneumonia (P23.-)
  • congenital syphilis (A50.-)
  • human immunodeficiency virus [HIV] disease (B20)
  • infant botulism (A48.51)
  • infectious diseases not specific to the perinatal period (A00-B99, J09, J10.-)
  • intestinal infectious disease (A00-A09)
  • laboratory evidence of human immunodeficiency virus [HIV] (R75)
  • tetanus neonatorum (A33)
Z21

None at this code

Code firstDiffers
P35-P39

None at this code

Z21
  • Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium, if applicable (O98.7-)
CategoryDiffers
P35-P39

P35 Congenital viral diseases

Z21

Is itself a category

ChapterDiffers
P35-P39

P00-P96 — Certain Conditions Originating in the Perinatal Period (P00-P96)

Z21

Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99)

IncludesDiffers
P35-P39
  • Infections acquired in utero, during birth via the umbilicus, or during the first 28 days after birth
Z21
  • HIV positive NOS

No Use additional code, Code also and 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, notes every code shares are dimmed.

Edit this comparisonCheck a whole claim

Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources