From the Research
The ICD-10 codes that cover getting a magnesium lab test include R79.0 (Abnormal level of blood mineral), E83.42 (Hypomagnesemia), and E83.41 (Hypermagnesemia), as these codes are most relevant to the clinical indication for the test, increasing the likelihood of insurance coverage 1. When ordering magnesium labs, it's essential to select the most specific code that reflects the clinical indication for the test.
- For routine screening or monitoring, Z00.00 (Encounter for general adult medical examination without abnormal findings) or Z13.9 (Encounter for screening, unspecified) may be appropriate.
- If checking magnesium levels due to medication effects, use T50.995A (Adverse effect of other drugs, medicaments and biological substances).
- For patients with specific conditions requiring magnesium monitoring, you can code the underlying condition such as N17.9 (Acute kidney failure, unspecified) or K59.0 (Constipation). Magnesium testing is commonly ordered to evaluate electrolyte imbalances, medication effects, or symptoms like muscle weakness, tremors, or cardiac arrhythmias, and recent studies have highlighted the importance of magnesium status in various clinical contexts, including COVID-19 1 and cardiovascular disease 2. The most recent and highest quality study, published in 2025, found that lower serum magnesium is associated with mortality in severe COVID-19, emphasizing the need for accurate magnesium testing and coding 1. Therefore, when ordering magnesium labs, it's crucial to prioritize the most specific and relevant ICD-10 codes to ensure accurate billing and insurance coverage.