E83.51

🧬 ICD-10-CM E83.51 — Hypocalcemia

Billable Code Confirmed

ICD-10-CM E83.51 is a valid, billable 5-character ICD-10-CM code for FY2025. The code structure is: E83 (category — Disorders of mineral metabolism) + .5 (subcategory — Disorders of calcium metabolism) + 1 (5th character — Hypocalcemia). No 6th or 7th character is required. This code is valid for claims submission from October 1, 2024 through September 30, 2025.

Non-Billable Parent Codes — Never Submit These

• ❌ E83.5 — 4-character subcategory header — missing the specific condition character; not billable
• ❌ E83 — 3-character category — no specificity; not billable

Always submit E83.51 (all 5 characters) when the provider has documented hypocalcemia as a confirmed diagnosis. When a more specific etiology code exists (e.g., hypoparathyroidism, hungry bone syndrome), use that code instead — see Excludes1 below.

Critical Distinction: Multiple Excludes1 Conditions — When NOT to Use E83.51

E83.51 has a significant Excludes1 list at the E83.5 subcategory level. The following conditions represent specific etiologic mechanisms of hypocalcemia that have their own dedicated ICD-10-CM codes and cannot be coded together with E83.51:

Condition	Correct Code Instead of / Alongside E83.51
Autosomal dominant hypocalcemia (genetic channelopathy)	E20.810 — Use instead of E83.51
Autoimmune hypoparathyroidism	E20.812 — Use instead of E83.51
Secondary hypoparathyroidism in diseases classified elsewhere	E20.811 — Use instead of E83.51
Hyperparathyroidism causing hypocalcemia (paradoxical)	E21.0-E21.3 — Use instead
Hungry bone syndrome (post-parathyroidectomy Ca sequestration)	E83.81 — Use instead of E83.51
Chondrocalcinosis	M11.1-M11.2 — Use instead

Additionally, at the E83 category level, the Excludes1 note prohibits using E83.51 alongside:

• Dietary calcium deficiency (E58) — use E58 when the deficiency is purely nutritional/dietary
• Vitamin D deficiency (E55.9, E55.0) — if hypocalcemia is solely attributable to vitamin D deficiency, code the vitamin D deficiency; E83.51 may be added as a manifestation when both are documented and both are managed
• Parathyroid disorders (E20-E21) — as above; parathyroid etiology takes precedence

Bottom line: E83.51 is appropriate for metabolic/pathological hypocalcemia where a specific excluded mechanism is NOT the primary cause — including post-surgical hypoparathyroidism (E89.2), CKD-mineral bone disorder, renal losses, malabsorption, or hypomagnesemia-driven hypocalcemia.

🔍 Code Description

ICD-10-CM E83.51 classifies hypocalcemia — an abnormally low serum (total) calcium level, generally defined as serum calcium below 8.5 mg/dL (2.12 mmol/L) or ionized calcium below 4.6 mg/dL (1.15 mmol/L). Calcium is the most abundant mineral in the human body and is critical for neuromuscular transmission, cardiac electrophysiology, bone mineralization, blood coagulation, and intracellular signaling.

Clinical severity correlates with both the absolute level and the rate of decline:

• Mild hypocalcemia (7.5-8.5 mg/dL): Often asymptomatic; perioral numbness, tingling in extremities
• Moderate hypocalcemia (7.0-7.5 mg/dL): Muscle cramps, carpopedal spasm, positive Chvostek’s sign, positive Trousseau’s sign
• Severe hypocalcemia (<7.0 mg/dL): Tetany, laryngospasm, bronchospasm, seizures, QTc prolongation, ventricular arrhythmias, heart failure — a life-threatening emergency

Common etiologies mapped to E83.51 (document and code the underlying cause separately when known):

• Post-surgical: Hypoparathyroidism following thyroid or parathyroid surgery (E89.2 — Post-procedural hypoparathyroidism; most common cause of acute inpatient hypocalcemia)
• Magnesium-driven: Hypomagnesemia (E83.42) impairing PTH secretion and end-organ PTH resistance — hypomagnesemia must be corrected first; code both E83.51 + E83.42
• Renal: CKD-mineral bone disorder (impaired renal 1-alpha-hydroxylase reducing calcitriol production); N18.x should be coded; calcitriol replacement indicated
• Malabsorption: Celiac disease, Crohn’s, short bowel syndrome, pancreatic insufficiency — code the GI condition additionally
• Vitamin D deficiency: When provider documents both vitamin D deficiency AND hypocalcemia as manifestation — code E55.x as etiology and E83.51 as manifestation (but NOT together when vitamin D deficiency alone fully explains it per Excludes1 guidance)
• Drug-induced: Bisphosphonates (post-zoledronic acid administration), denosumab, cinacalcet, foscarnet, citrate (from massive blood transfusion) — add adverse effect code from T-series
• Pancreatitis: Calcium saponification in fat necrosis (K85.xx) — code pancreatitis additionally
• Sepsis/Critical illness: Multifactorial in ICU; hypoalbuminemia (check ionized Ca), inflammatory cytokines

Note

Albumin-corrected calcium matters clinically but NOT for coding. Total serum calcium is influenced by albumin levels. A “low” total calcium in a hypoalbuminemic patient may represent a normal ionized calcium. However, for ICD-10-CM coding purposes, the physician must document the diagnosis of hypocalcemia — coders do not adjust for albumin independently. Always query the provider when only an uncorrected low total calcium appears in the lab results alongside hypoalbuminemia.

🌳 Code Tree / Hierarchy

E83  Disorders of mineral metabolism ❌ Non-billable
│
├── E83.0  Disorders of copper metabolism ❌ Non-billable header
├── E83.1  Disorders of iron metabolism ❌ Non-billable header
├── E83.2  Disorders of zinc metabolism ❌ Non-billable header
├── E83.3  Disorders of phosphorus metabolism ❌ Non-billable header
│
├── E83.4  Disorders of magnesium metabolism ❌ Non-billable header
│   ├── E83.40  Disorders of magnesium metabolism, unspecified ✅
│   ├── E83.41  Hypermagnesemia ✅
│   ├── E83.42  Hypomagnesemia ✅ (frequently co-coded with E83.51)
│   └── E83.49  Other disorders of magnesium metabolism ✅
│
├── E83.5  Disorders of calcium metabolism ❌ Non-billable header
│   │       [Excludes1: see full list in IMPORTANT callout above]
│   │
│   ├── E83.50  Unspecified disorder of calcium metabolism ✅ Billable
│   │           (Avoid if hypocalcemia or hypercalcemia is specified)
│   ├── E83.51  HYPOCALCEMIA ◀ THIS CODE ✅ Billable
│   ├── E83.52  Hypercalcemia ✅ Billable (opposite condition; not reported with E83.51)
│   └── E83.59  Other disorders of calcium metabolism ✅ Billable
│               (e.g., idiopathic hypercalciuria, calcium nephrolithiasis-related)
│
├── E83.8  Other disorders of mineral metabolism ❌ Non-billable header
│   ├── E83.81  Hungry bone syndrome ✅ (Excludes1 to E83.51 — use instead of E83.51
│   │           for post-parathyroidectomy Ca sequestration; NOT the same as E89.2)
│   └── E83.89  Other disorders of mineral metabolism ✅
│
└── E83.9  Disorder of mineral metabolism, unspecified ✅
           (Avoid when a specific subcategory code is available)

Related codes in other categories (commonly coded alongside E83.51):

E89.2   Post-procedural hypoparathyroidism (most common surgical cause of E83.51)
E20.810 Autosomal dominant hypocalcemia (Excludes1 — use INSTEAD of E83.51)
E20.811 Secondary hypoparathyroidism in diseases classified elsewhere (Excludes1)
E20.812 Autoimmune hypoparathyroidism (Excludes1)
E83.42  Hypomagnesemia (frequently causes E83.51; code BOTH when both documented)
E55.9   Vitamin D deficiency, unspecified (etiology for some cases of E83.51)
N18.xx  Chronic kidney disease (CKD-mineral bone disorder)
K85.xx  Acute pancreatitis (calcium saponification)
Z79.899 Other long term (current) drug therapy (bisphosphonate, denosumab)

✅ Includes

The following clinical terms, documentation phrases, and clinical scenarios map to E83.51:

• Hypocalcemia — any cause, in non-neonatal patients (for neonatal, use P71.1 — Other neonatal hypocalcemia)
• Low serum calcium / Low ionized calcium — when provider documents this as a diagnosis, not merely as a lab finding
• Post-surgical hypocalcemia when documented as a result of post-operative hypoparathyroidism (E89.2 is coded as primary etiology; E83.51 may be added as the metabolic manifestation when both are clinically managed)
• Hypocalcemia in the setting of CKD/renal failure (code N18.x additionally)
• Hypocalcemia secondary to hypomagnesemia (code E83.42 additionally)
• Hypocalcemia complicating pancreatitis (code K85.xx additionally)
• Drug-induced hypocalcemia (add adverse effect T-code from Table of Drugs and Chemicals)
• Hypocalcemia complicating malabsorption (code GI disorder additionally)

❌ Excludes

Excludes1 at E83.5 Subcategory Level — Cannot be coded WITH E83.51

These conditions represent specific, distinct etiologic mechanisms of hypocalcemia — when the provider documents one of these, use that code instead of E83.51:

• Autosomal dominant hypocalcemia (E20.810) — CACNA1A or CASR gain-of-function mutation; hereditary; Excludes1 — use E20.810 instead of E83.51
• Autoimmune hypoparathyroidism (E20.812) — immune-mediated PTH gland destruction; Excludes1 — use E20.812 instead
• Secondary hypoparathyroidism in diseases classified elsewhere (E20.811) — hypoparathyroidism secondary to another disease; Excludes1
• Hyperparathyroidism (E21.0-E21.3) — generally causes hypercalcemia, but when paradoxical or coded in context, cannot appear with E83.51 per Excludes1
• Hungry bone syndrome (E83.81) — acute post-parathyroidectomy calcium sequestration into bone; Excludes1 at E83.5 level — a distinct condition from surgical hypoparathyroidism
• Chondrocalcinosis (M11.10-M11.29) — calcium pyrophosphate crystal deposition disorder; Excludes1

Excludes1 at E83 Category Level — Cannot be coded WITH E83.51

• Dietary calcium deficiency (E58) — purely nutritional/dietary cause; use E58 if that is the documented sole etiology
• Vitamin D deficiency (E55.0, E55.9) — when vitamin D deficiency is the sole documented cause of low calcium; however, when both vitamin D deficiency AND hypocalcemia are separately documented and managed, some coding advisors support coding both — always query payer guidelines and CDI leadership for specific scenarios
• Parathyroid disorders (E20-E21) — parathyroid etiology takes precedence; code the parathyroid disorder instead

Excludes1 for Neonatal Presentation

• Neonatal hypocalcemia (P71.1 — Other neonatal hypocalcemia) — for patients who are neonates; E83.51 is for non-neonatal patients only

Excludes2 — Can be coded together if both are present

• Disorders of fluid, electrolyte, and acid-base balance (E87.x) — including hypokalemia (E87.6), hyponatremia, etc.; code together when co-documented
• Hypomagnesemia (E83.42) — can and should be coded alongside E83.51 when both are documented and managed; hypomagnesemia is a primary driver of hypocalcemia
• Malnutrition codes (E40-E46) — reportable alongside E83.51; malnutrition is HCC-bearing
• CKD (N18.xx) — code together; CKD-mineral bone disorder is a recognized and important comorbidity

🛠️ CPT Procedural Crosswalk — wRVU & Assistant Payable Status

The following CPT and HCPCS codes are most commonly associated with the diagnosis and treatment of E83.51. Acute symptomatic hypocalcemia (tetany, laryngospasm, seizure) requires emergent IV calcium replacement; chronic hypocalcemia is managed with oral calcium and active vitamin D.

CPT / HCPCS	Description	wRVU (Facility)	Asst. Surgeon Payable?	Co-Surgeon Payable?
96374	Intravenous push, single or initial substance/drug — for acute IV bolus of calcium gluconate in symptomatic/emergency hypocalcemia	0.18	❌ No	❌ No
96365	Intravenous infusion, therapeutic; initial, up to 1 hour — for continuous calcium infusion in moderate-to-severe cases	0.17	❌ No	❌ No
96366	IV infusion, each additional hour (add-on to 96365)	0.10	❌ No	❌ No
J0610	Injection, calcium gluconate, per 10 ml — standard IV calcium for acute hypocalcemia replacement (1 g calcium gluconate = 10 ml of 10% solution = 1 unit)	N/A (drug)	N/A	N/A
J0636	Injection, calcitriol, 0.1 mcg — active vitamin D (1,25-dihydroxyvitamin D3) for CKD-related or hypoparathyroidism-driven hypocalcemia	N/A (drug)	N/A	N/A
82310	Calcium; total — serum total calcium; primary diagnostic and monitoring lab	0.00 (lab)	N/A	N/A
82330	Calcium; ionized — more accurate than total calcium, especially in hypoalbuminemic or critically ill patients	0.00 (lab)	N/A	N/A
80047	Basic Metabolic Panel with ionized calcium — includes ionized Ca (82330); more comprehensive than BMP	0.00 (lab)	N/A	N/A
83970	Parathyroid hormone (PTH) — essential workup for hypocalcemia etiology; differentiates hypoparathyroid from non-parathyroid causes	0.00 (lab)	N/A	N/A
82652	Vitamin D, 25-hydroxy — screens for vitamin D deficiency as a contributing etiology	0.00 (lab)	N/A	N/A
83735	Magnesium (Mg) — always check Mg in hypocalcemic patients; hypomagnesemia drives refractory hypocalcemia	0.00 (lab)	N/A	N/A
93000	Electrocardiogram, routine; with interpretation and report — QTc prolongation monitoring; hypocalcemia prolongs QTc → torsades de pointes risk	0.17	❌ No	❌ No
99291	Critical care, evaluation and management; first 30-74 minutes — for severe hypocalcemia with tetany, laryngospasm, seizures, or arrhythmia	4.50	❌ No	❌ No
99292	Critical care; each additional 30 minutes (add-on to 99291)	2.25	❌ No	❌ No

⚠️ Drug Billing Note — J0610 Units: Calcium gluconate 10% injection = 10 ml per 10 mL vial = 1 g per vial = 1 unit of J0610. Standard acute hypocalcemia dosing:

• Symptomatic/emergency: 1-2 g IV bolus over 10-20 min = 1-2 units of J0610 via 96374
• Maintenance infusion: 0.5-1.5 mg/kg/hr of elemental calcium — calculate total grams, report J-code units accordingly via 96365/96366 Always append -JW or -JZ to J0610 per CR 13056 (effective 7/1/2023) for wastage attestation.

⚠️ Lab Coding Note: 82310 (total calcium) is NOT the same as 82330 (ionized calcium). These are separately billable codes and reflect clinically different measurements. 80047 (BMP with ionized Ca) includes ionized calcium and is the preferred panel in critical care settings where albumin status may distort total calcium interpretation. 83970 (PTH) and 82652 (vitamin D) are the cornerstone workup labs for new hypocalcemia — each billed separately.

💊 Coding Scenarios

Scenario 1 — Post-Thyroidectomy Hypocalcemia, Inpatient

Clinical Vignette: A 48-year-old female undergoes total thyroidectomy for papillary thyroid cancer. On postoperative day 1, she develops perioral tingling, muscle cramps, and a positive Chvostek’s sign. Serum calcium is 7.1 mg/dL. PTH is undetectable. The surgeon documents “acute post-surgical hypocalcemia secondary to hypoparathyroidism.” IV calcium gluconate is initiated.

CPT / HCPCS Codes:

• 96374 — IV push, calcium gluconate acute bolus
• 96365 + 96366 — Continuous calcium infusion (subsequent hours)
• J0610 × 4 — Calcium gluconate 4 g total administered
• 82310 — Serum calcium monitoring
• 83970 — PTH level (confirms hypoparathyroidism)

ICD-10-CM:

• Principal Dx: E89.2 — Post-procedural hypoparathyroidism (the surgically-caused mechanism — this is the appropriate sequencing; the post-surgical hypoparathyroidism is what drove the complication)
• Secondary Dx: E83.51 — Hypocalcemia (the metabolic manifestation, separately clinically managed with calcium infusion)
• Secondary Dx: C73 — Malignant neoplasm of thyroid gland (the indication for surgery)

🏥 Inpatient Coder Tip: Post-surgical hypoparathyroidism (E89.2) and hypocalcemia (E83.51) are NOT an Excludes1 pair — both can be coded together. E89.2 is the etiology (post-procedural parathyroid dysfunction) and E83.51 is the metabolic manifestation (low serum calcium). This is distinct from the Excludes1 conditions at E83.5 (autoimmune, autosomal dominant, or secondary hypoparathyroidism coded under E20.x — those CANNOT be coded with E83.51). Always capture C73 or the indication for the thyroidectomy to establish complete clinical context.

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Scenario 2 — Hypocalcemia with Hypomagnesemia, Code Both

Clinical Vignette: A 61-year-old male on long-term PPI therapy and loop diuretics for CHF is admitted with tetany and muscle weakness. Labs: serum Mg 0.9 mg/dL, serum Ca 6.8 mg/dL, ionized Ca 0.78 mmol/L, K+ 3.1 mEq/L. The hospitalist documents “severe hypocalcemia secondary to hypomagnesemia; also with hypokalemia.” IV magnesium sulfate and calcium gluconate are administered concurrently.

CPT / HCPCS Codes:

• 96365 × 2 — Two separate infusions (Mg sulfate and calcium gluconate run concurrently or sequentially)
• 96366 — Additional hours as needed
• J3475 × 8 — Magnesium sulfate 4 g (8 × 500 mg units)
• J0610 × 2 — Calcium gluconate 2 g IV
• 82310 — Serum calcium monitoring
• 83735 — Serum magnesium monitoring
• 80048 — BMP (monitoring K+, creatinine)
• 93000 — EKG (QTc monitoring for both hypocalcemia and hypokalemia arrhythmia risk)

ICD-10-CM:

• Principal Dx: E83.51 — Hypocalcemia (most severe and immediately life-threatening; reason for admission after study)
• Secondary Dx: E83.42 — Hypomagnesemia (documented cause of the hypocalcemia; also separately managed)
• Secondary Dx: E87.6 — Hypokalemia (co-documented, separately managed)
• Secondary Dx: I50.9 — Heart failure, unspecified (underlying condition contributing to diuretic use)
• Secondary Dx: T47.1X5A — Adverse effect of other antacids and anti-gastric-secretion drugs (PPI), initial encounter (contributing cause of hypomagnesemia)

🏥 Inpatient Coder Tip: E83.51 and E83.42 are NOT Excludes1 to each other — code both when documented. All three electrolyte disorders (E83.51, E83.42, E87.6) are separately documentable and billable; collapsing them into one unspecified electrolyte code (E87.8) loses clinical specificity and DRG accuracy. The PPI adverse effect code (T47.1X5A) links the drug to the magnesium depletion — always capture iatrogenic causes when documented.

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Scenario 3 — CKD-Mineral Bone Disorder with Hypocalcemia, Outpatient

Clinical Vignette: A 73-year-old female with CKD stage 4 presents to nephrology clinic with fatigue and muscle cramps. Serum Ca is 7.8 mg/dL, intact PTH is elevated at 310 pg/mL (secondary hyperparathyroidism), 25-OH vitamin D is 12 ng/mL. The nephrologist documents “hypocalcemia due to CKD-mineral bone disorder; secondary hyperparathyroidism; vitamin D deficiency.” Calcitriol 0.25 mcg oral daily and calcium carbonate are prescribed; IV calcitriol infusion is initiated for one visit.

CPT / HCPCS Codes:

• 99214 — Office visit, moderate medical decision making
• 96365 — IV calcitriol infusion (if given IV in office)
• J0636 × 2 — Calcitriol injection, 0.1 mcg per unit (0.25 mcg = ~2-3 units; verify exact dosing)
• 82310 — Serum calcium
• 83970 — PTH level
• 82652 — Vitamin D, 25-hydroxy

ICD-10-CM:

• E83.51 — Hypocalcemia (confirmed diagnosis, managed with calcitriol and calcium)
• N18.4 — Chronic kidney disease, stage 4 (underlying etiology — HCC 137; always capture CKD stage)
• E21.1 — Secondary hyperparathyroidism, not elsewhere classified (documented reactive PTH elevation)
• E55.9 — Vitamin D deficiency, unspecified (documented contributing factor; provider manages this separately)

🏥 Outpatient Coder Tip: N18.4 carries HCC 137 — this is a critical secondary diagnosis capture. CKD-related hypocalcemia is among the most HCC-impactful clinical contexts for E83.51. Always ensure the nephrologist documents the CKD stage explicitly; “CKD” without a stage cannot be coded with maximum specificity and may not capture the correct HCC. E21.1 (secondary hyperparathyroidism) is separately billable and should be coded when documented — it is NOT in the Excludes1 list for E83.51 at E83.5.

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Scenario 4 — CDI Query: Albumin-Corrected vs. True Hypocalcemia

Clinical Vignette: A coder reviews an ICU admission chart. Total serum calcium is documented at 7.4 mg/dL. Serum albumin is 1.8 g/dL (critically low). The nursing note reads “hypocalcemia — per lab critical value protocol, notified physician.” No physician documentation confirms a hypocalcemia diagnosis. The ionized calcium level is 1.09 mmol/L (within normal range when albumin-corrected).

Action / Outcome:

The coder should NOT assign E83.51 based solely on the low total calcium lab value and nursing notification. Two issues are present:

1. No physician-documented diagnosis — lab values and nursing notes alone do not authorize an ICD-10-CM code per Official Guidelines Section III
2. Clinical context suggests the low total Ca may be albumin-driven — the ionized calcium (the physiologically active form) is actually normal, suggesting this is NOT true hypocalcemia

Correct Action: Submit a CDI query to the attending/intensivist: “The patient’s serum total calcium was 7.4 mg/dL with albumin of 1.8 g/dL. The ionized calcium is within normal limits at 1.09 mmol/L. Do you believe the patient has clinically significant hypocalcemia requiring treatment, or is this lab finding explained by the low albumin level? Please document your clinical assessment.”

If physician confirms true hypocalcemia: Code E83.51 as secondary diagnosis. If physician confirms albumin-effect, no true hypocalcemia: Do not code E83.51; the low total calcium is a lab artifact, not a clinical diagnosis.

⚠️ Coding Pitfalls and Tips

	Pitfall or Tip
❌	Do not code E83.51 from a lab value alone. ICD-10-CM requires a physician-documented diagnosis — “hypocalcemia,” “low calcium,” or “calcium deficiency” must appear in the provider’s assessment/plan, progress notes, or discharge summary before E83.51 can be assigned
❌	Do not use E83.51 when an Excludes1 etiology is the documented cause. If the provider documents autoimmune hypoparathyroidism (E20.812), autosomal dominant hypocalcemia (E20.810), hungry bone syndrome (E83.81), or chondrocalcinosis (M11.x), use those codes instead of E83.51 — these are Excludes1 at the E83.5 subcategory level
❌	Do not confuse E83.51 with E58 (dietary calcium deficiency). These are Excludes1 at the E83 category level. When the provider documents “dietary calcium deficiency” as the sole cause, E58 applies. When the cause is metabolic/pathological (surgery, CKD, drugs, hypomagnesemia), E83.51 applies
❌	Do not code E83.51 for neonates. Neonatal hypocalcemia uses P71.1 (Other neonatal hypocalcemia); E83.51 is for non-neonatal patients
❌	Do not default to E83.51 when a more specific calcium disorder code is available. For example, hungry bone syndrome (E83.81) is a distinct Excludes1 condition that occurs post-parathyroidectomy due to rapid bone calcium uptake — it is NOT coded as E83.51
❌	Do not assume total serum calcium equals ionized calcium. In hypoalbuminemic patients, low total calcium may reflect reduced protein binding, not true ionized hypocalcemia. Always query the provider when ionized calcium is normal but total calcium is low, especially in ICU patients
✅	Always capture the underlying etiology as an additional code. Post-surgical (E89.2), CKD (N18.x), hypomagnesemia (E83.42), pancreatitis (K85.xx) — these are NOT Excludes1 to E83.51 (only the E20.x hypoparathyroidism subcategory codes and E83.81 are Excludes1); capturing etiology provides clinical completeness and supports medical necessity
✅	Always capture co-existing HCC-bearing conditions. E83.51 itself carries no HCC weight — but N18.x (CKD → HCC 136/137), malnutrition (E40-E46), and malignancy are commonly co-occurring conditions that must be captured as secondary diagnoses for full risk adjustment accuracy
✅	Code all co-existing electrolyte disorders separately. E83.51 + E83.42 (hypomagnesemia) + E87.6 (hypokalemia) are each separately billable when documented and managed; do not collapse into a single unspecified code
✅	Monitor lab codes are all separate from E83.51 itself. 82310 (total Ca), 82330 (ionized Ca), 83970 (PTH), 82652 (vitamin D), and 83735 (Mg) are all separately billable lab CPT codes; ensure these are linked appropriately to E83.51 for medical necessity on outpatient claims

📚 Sources

1. CMS/NCHS. ICD-10-CM Official Guidelines for Coding and Reporting, FY2025. Tabular List — E83.51 Hypocalcemia; Excludes1/Excludes2 notes at E83 and E83.5; Section I.C.4 — Endocrine, Nutritional, and Metabolic Diseases; Section III — Reporting Additional Diagnoses.

2. World Health Organization / CMS. ICD-10-CM Tabular List of Diseases and Injuries, FY2025 Release. Category E83 — Disorders of mineral metabolism; E83.5 Excludes1 notes; Subcategory detail for E83.51.

3. Centers for Medicare & Medicaid Services. MS-DRG v37.2 / v41 (FY2025) Definitions Manual. MDC 10 — Endocrine, Nutritional and Metabolic Diseases & Disorders; DRG 640-641 (E8351 Hypocalcemia confirmed in grouper table).

4. CMS. Billing and Coding: Assays for Vitamins and Metabolic Function (A56416). Coverage guidance linking E83.51 to laboratory testing including 82652 (vitamin D) and 83970 (PTH).

5. CMS CR 13056. JW/JZ Modifier Requirements for Medicare Part B Drug Claims. Effective July 1, 2023 — applicable to J0610, J0636, and all Part B drug claims.

6. American Medical Association (AMA). CPT 2024/2025 Professional Edition. Infusion therapy codes 96374, 96365, 96366; pathology/laboratory codes 82310, 82330, 83970, 82652, 83735.

7. NCBI StatPearls. Calcium Gluconate. Hypocalcemia treatment, dosing, and HCPCS J0610 drug billing reference. Updated February 2024.

8. AAPC. ICD-10-CM Code E83.51 — Hypocalcemia. Codify reference, Excludes1 notation at E83.5. FY2025.