Where this LCD applies
Each contract number is a jurisdiction on the remittance; the policy binds claims processed under these contracts and no others.
Billing and coding: diagnoses and procedure codes
Since 2019 the codes live in the companion article rather than the LCD. Billing and Coding A57189 (Billing and Coding: Serum Magnesium) carries the diagnosis and procedure lists the contractor loads as the claims edit. CPT codes are shown as bare numbers because the descriptors are licensed by the AMA; HCPCS Level II descriptors are public and shown.
A57189: Billing and Coding: Serum Magnesium (Billing and Coding, effective 2025-10-16)
- Covered ICD-10-CM codes
- 1405
- 1 group
- Non-covered ICD-10-CM codes
- 0
- Procedure codes listed
- 1
- Full article
- cms.gov record
| ICD-10-CM | Description (FY2027) |
|---|---|
| D56.1 | — |
| D57.02 | — |
| D57.1 | — |
| D57.212 | — |
| D57.412 | — |
| D57.812 | — |
| D68.8 | — |
| D73.1 | — |
| D73.2 | — |
| D73.81 | — |
| D73.89 | — |
| E03.5 | — |
| E08.00 | — |
| E08.01 | — |
| E08.10 | — |
| E08.11 | — |
| E08.21 | — |
| E08.22 | — |
| E08.29 | — |
| E08.3211 | — |
| E08.3212 | — |
| E08.3213 | — |
| E08.3291 | — |
| E08.3292 | — |
Procedure codes: 83735.
Coverage indications, limitations and medical necessity
Note: Providers should seek information related to National Coverage Determinations (NCD) and other Centers for Medicare & Medicaid Services (CMS) instructions in CMS Manuals. This LCD only pertains to the contractor's discretionary coverage related to this service.
Magnesium is a mineral required by the body for the use of adenosine triphosphate (ATP) as a source of energy. It is also necessary for neuromuscular irritability and blood clotting. Magnesium deficiency produces neuromuscular disorders. It may cause weakness, tremors, tetany, and convulsions. Hypomagnesemia is associated with hypocalcemia, hypokalemia, long-term hyperalimentation, intravenous therapy, diabetes mellitus (especially during treatment of ketoacidosis); alcoholism and other types of malnutrition; malabsorption; hyperparathyroidism; dialysis; pregnancy; and hyperaldosteronism. The following are other conditions that may cause magnesium deficiencies
• Renal loss of magnesium occurs with cis-platinum therapy.
• Hypomagnesemia may also be induced by amphotericin or anti-EGFR (some monoclonal antibodies) toxicity.
• Magnesium deficiency is described with cardiac arrhythmias. There is evidence that magnesium may cause arrhythmias.
Indications:
Utilization of certain cardiac drugs which cause adverse effects in the presence of low magnesium (i.e., quinidine, procainamide, and disopyramide phosphate or Norpace). Patients taking these drugs should have their magnesium checked approximately once every six months.
• Long term parenteral nutrition. Patients on long term parenteral nutrition that are otherwise asymptomatic should have their serum magnesium checked monthly.
• Malabsorption syndrome. The frequency should depend on the severity of the syndrome, but once the patient's level is stabilized, a monthly check should be adequate.
• Renal loss secondary to diuretic use.
• Chronic alcoholism, diabetic acidosis, and renal tubular acidosis. These patients should be followed on an as needed basis according to their symptomatology. Without symptoms, they should be checked no more than annually.
• Chronic diarrhea, otherwise unexplained and persistent.
• Prolonged nasogastric suction greater than five days. These patients should have a magnesium check every two to three weeks.
• Cisplatin treatment.
• Amphotericin treatment
• EGFR monoclonal antibodies
• Patients receiving IV magnesium therapy for a low serum level. Serum level should be monitored appropriately.
• Patients with hypocalcemia. If the hypocalcemia persists, the level should probably be checked on a six-month basis as long as the patient does not have symptoms of arrhythmias that would warrant closer follow up.
• Lethargy and confusion that are not otherwise explained. Once a patient has been diagnosed with mental health processes such as Alzheimer or psychotic depression, etc., there is no indication to follow their magnesium level on a regular basis.
• Patients receiving oral magnesium in the face of impaired renal function should have their magnesium level checked on a monthly basis.
Other clinical situations:
• Pre-eclampsia
• Unexplained muscular paralysis
• Neuromuscular irritability
• Blood clotting abnormalities
• Evidence (mixed) that magnesium levels are low and increased magnesium may benefit patients with sickle cell anemia, beta thalassemia and hypersplenism– more recent articles dispute this.
• Long Q-T syndrome, torsades de pointes and ventricular arrhythmias.
Summary of evidence (opening)
NA
the full summary and analysis of evidence are in the CMS record.
Dates, lineage and related policies
- Original determination effective
- 2017-03-13
- Current revision effective
- 2025-10-16
- Last reviewed by the contractor
- 2021-03-02
- MCD version
- 20
Other related documents: A55361 (Response to Comments), A55362 (Response to Comments).
Using this policy on a claim
Match the documented indication to the covered indications above before the service is scheduled, carry a diagnosis from the article's covered list on the claim line, and keep the elements the documentation section asks for in the record, because the contractor can request it later through medical review. A denial under this policy arrives as CARC 50 with remark N115; the LCD lookup guide walks through the appeal path and the Advance Beneficiary Notice rules, and the Noridian Healthcare Solutions, LLC hub lists every other active policy from the same contractor.
Frequently asked questions
What does LCD L36702 cover?
Note: Providers should seek information related to National Coverage Determinations (NCD) and other Centers for Medicare & Medicaid Services (CMS) instructions in CMS Manuals. This LCD only pertains to the contractor's discretionary coverage related to this service. The full indications and limitations are reproduced on this page from the CMS Medicare Coverage Database export of September 24, 2026.
Which states does LCD L36702 apply to?
Noridian Healthcare Solutions, LLC applies it to Medicare claims in AK, AS, AZ, CA, CNMI, GU, HI, ID, MT, ND, NF, NV, OR, SD, SF, UT, WA, WY. A Local Coverage Determination binds only the contractor that wrote it; the same service in another jurisdiction is judged under that contractor's own policy or, where none exists, claim by claim.
Which diagnosis codes support medical necessity under LCD L36702?
The companion billing and coding article A57189 lists 1,405 ICD-10-CM codes in 1 group that support medical necessity; the first 24 appear on this page and the complete list is in the article on cms.gov.
How do I appeal a denial under LCD L36702?
The remittance carries claim adjustment reason code 50 with remark code N115, naming the LCD. Compare the documented indication with the policy's covered indications and the article's diagnosis list, then file a redetermination within 120 days with the record attached; if the service genuinely falls outside the policy, the patient can be billed only when a valid Advance Beneficiary Notice was obtained before the service.
Sources
Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-02. Verify against the primary file before billing or contracting decisions.
- Medicare Coverage Database, current LCD exportVersion MCD release 2026-09-24 · effective 2026-09-20 · file lcd.csvSHA-256 2fcc4251b6ddd1eb…
- Medicare Coverage Database, current Billing and Coding Articles exportVersion MCD release 2026-09-24 · effective 2026-09-20 · file article.csvSHA-256 f31932f1df3b4035…
- ICD-10-CM FY2027 code descriptionsVersion FY2027 · effective 2026-10-01 · file icd10cm_codes_2027.txtSHA-256 3c0583a38ee0e848…
Disclaimer
The policy text and code lists are reproduced from the CMS Medicare Coverage Database export as an operational reference. Verify against the current LCD and article on cms.gov before billing; coverage depends on the full record and the contractor. Not legal, clinical or billing advice.