P71.2 ICD-10-CM Code: Neonatal hypomagnesemia

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for P71.2 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on P71.2 itself; “inherited from” names the category or block whose note applies here.

Indexed Clinical Terms (1)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Hypomagnesemia, neonatal

Don’t confuse P71.2 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of P71.2 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• P71.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Transitory neonatal disorder of calcium and magnesium metabolism, unspecified” takes P71.9; specificity in the record moves it back here.

  Full comparison: P71.2 vs P71.9 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name P71.2 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: R79.0 — Abnormal level of blood mineral.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Excludes2 note: P00 — Newborn affected by maternal conditions that may be unrelated to present pregnancy (via P71.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 44 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 791 (MDC 15), DRG 793 (MDC 15).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):PNL013 — Other specified and unspecified perinatal conditions (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

P29.89 — Other cardiovascular disorders originating in the perinatal period, P29.9 — Cardiovascular disorder originating in the perinatal period, unspecified, P70.0 — Syndrome of infant of mother with gestational diabetes, P70.1 — Syndrome of infant of a diabetic mother, P70.2 — Neonatal diabetes mellitus, P70.3 — Iatrogenic neonatal hypoglycemia, P70.4 — Other neonatal hypoglycemia, P70.9 — Transitory disorder of carbohydrate metabolism of newborn, unspecified, P71.0 — Cow's milk hypocalcemia in newborn, P71.1 — Other neonatal hypocalcemia, P71.3 — Neonatal tetany without calcium or magnesium deficiency, P71.4 — Transitory neonatal hypoparathyroidism, P71.8 — Other transitory neonatal disorders of calcium and magnesium metabolism, P71.9 — Transitory neonatal disorder of calcium and magnesium metabolism, unspecified, P72.1 — Transitory neonatal hyperthyroidism, P72.9 — Transitory neonatal endocrine disorder, unspecified, P74.0 — Late metabolic acidosis of newborn, P74.1 — Dehydration of newborn, P74.21 — Hypernatremia of newborn, P74.22 — Hyponatremia of newborn, +23 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other specified and unspecified perinatal conditions).

P29.9 — Cardiovascular disorder originating in the perinatal period, unspecified, P70.0 — Syndrome of infant of mother with gestational diabetes, P70.1 — Syndrome of infant of a diabetic mother, P70.2 — Neonatal diabetes mellitus, P70.3 — Iatrogenic neonatal hypoglycemia, P70.4 — Other neonatal hypoglycemia, P70.8 — Other transitory disorders of carbohydrate metabolism of newborn, P70.9 — Transitory disorder of carbohydrate metabolism of newborn, unspecified, P71.0 — Cow's milk hypocalcemia in newborn, P71.1 — Other neonatal hypocalcemia, P71.3 — Neonatal tetany without calcium or magnesium deficiency, P71.4 — Transitory neonatal hypoparathyroidism, P71.8 — Other transitory neonatal disorders of calcium and magnesium metabolism, P71.9 — Transitory neonatal disorder of calcium and magnesium metabolism, unspecified, P72.0 — Neonatal goiter, not elsewhere classified, P72.1 — Transitory neonatal hyperthyroidism, P72.2 — Other transitory neonatal disorders of thyroid function, not elsewhere classified, P72.8 — Other specified transitory neonatal endocrine disorders, P72.9 — Transitory neonatal endocrine disorder, unspecified, P74.0 — Late metabolic acidosis of newborn, +74 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Hypomagnesemia”; these codes share that main term but sit in a different category of the Tabular List.

E83.42 — Hypomagnesemia

Contextual Map

Every relationship of P71.2 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run P71.2 with these 2 related codes in Claim Check

Hierarchy

• P00-P96 — Chapter 16: Certain Conditions Originating in the Perinatal Period (P00-P96) (P00-P96)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• P70-P74 — Transitory endocrine and metabolic disorders specific to newborn[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• R79.0 — Abnormal level of blood mineral[Excludes1]: “neonatal hypomagnesemia (P71.2)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• P00 — Newborn affected by maternal conditions that may be unrelated to present pregnancy[Excludes2](via P71.-): “newborn affected by maternal endocrine and metabolic disorders (P70-P74)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• PNL013 — Other specified and unspecified perinatal conditions[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 791 — PREMATURITY WITH MAJOR PROBLEMS[MS-DRG]: “PREMATURITY WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS[MS-DRG]: “FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 15 — Newborns and Other Neonates with Conditions Originating in Perinatal Period[MDC crossing]: “Newborns and Other Neonates with Conditions Originating in Perinatal Period — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Hypomagnesemia, neonatal[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• P71 — Transitory neonatal disorders of calcium and magnesium metabolism[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• P71.0 — Cow's milk hypocalcemia in newborn[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• P71.1 — Other neonatal hypocalcemia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• P71.3 — Neonatal tetany without calcium or magnesium deficiency[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• P71.4 — Transitory neonatal hypoparathyroidism[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• P71.8 — Other transitory neonatal disorders of calcium and magnesium metabolism[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• P71.9 — Transitory neonatal disorder of calcium and magnesium metabolism, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to P71.2 in its code family, with their registry titles.

• P71 — Transitory neonatal disorders of calcium and magnesium metabolism
• P71.0 — Cow's milk hypocalcemia in newborn
• P71.1 — Other neonatal hypocalcemia
• P71.3 — Neonatal tetany without calcium or magnesium deficiency
• P71.4 — Transitory neonatal hypoparathyroidism
• P71.8 — Other transitory neonatal disorders of calcium and magnesium metabolism
• P71.9 — Transitory neonatal disorder of calcium and magnesium metabolism, unspecified

View all codes in the P71 family