Other methemoglobinemias

This code signifies a group of rare blood disorders characterized by abnormally high levels of methemoglobin in red blood cells, leading to impaired oxygen delivery to tissues. These conditions are distinct from congenital or acquired enzyme deficiencies specifically coded elsewhere.

This code is appropriate for documenting methemoglobinemia cases that do not fit the more specific categories of congenital NADH methemoglobin reductase deficiency or acquired toxic methemoglobinemia. Documentation should clearly indicate a diagnosis of methemoglobinemia without specifying a known enzymatic defect or external causative agent.

• Ensure documentation explicitly rules out congenital enzyme deficiencies (e.g., cytochrome b5 reductase deficiency) and acquired toxic causes (e.g., drug-induced).
• Avoid using this code if a more specific methemoglobinemia diagnosis (e.g., due to a specific drug or chemical) is documented.
• Review the patient's medication list and exposure history to differentiate from acquired forms.