How Do I Code Diabetes With Hyperglycemia or Hypoglycemia? E11.65, E11.64-, and the E16.A Level

Both directions of blood glucose have their own combination codes in the diabetes categories, and the classification closes the symptom-code exits on both sides. For high glucose, category E10 carries an Excludes1 for “hyperglycemia NOS (R73.9)” — R73.9 is for hyperglycemia in a patient without a diabetes diagnosis; in a diabetic patient the Index route “Diabetes › type 2 › with › hyperglycemia” gives E11.65. For low glucose, E16.2, Hypoglycemia, unspecified, carries an Excludes1 for “diabetes with hypoglycemia (E08.649, E10.649, E11.649, E13.649),” and the Index route gives E11.649.

The hypoglycemia code also asks for a second code the hyperglycemia code does not: E11.64 carries “Use additional code for hypoglycemia level, if applicable (E16.A-).” The levels are E16.A1, E16.A2 and E16.A3, assigned only when the provider documents the level — the coding sources give no glucose thresholds.

1. Confirm the diabetes diagnosis. Without it, high glucose is R73.9 (or R73.03 for documented prediabetes) and low glucose is E16.2.
2. Hyperglycemia documented — “uncontrolled,” “poorly controlled,” or “hyperglycemia” in the record: E11.65. The E08, E09 and E13 categories carry the same .65 code.
3. Hypoglycemia documented: E11.649 without coma, E11.641 with coma.
4. Hypoglycemia level documented (level 1, 2 or 3): add E16.A1, E16.A2 or E16.A3 after the E11.64- code, per its Use Additional Code note.
5. If the hypoglycemia is a drug event — an insulin overdose, or an underdose of an antidiabetic — the T38.3X- poisoning or underdosing code applies with the diabetes code, following Section I.C.19.e; the poisoning guide linked below walks the columns. Section I.C.4.a.5 covers the insulin-pump case.
6. Add the Z79 control code, remembering that Z79.4 is not assigned for insulin given temporarily to bring glucose under control (I.C.4.a.3).

1. Type 2 diabetes, “poorly controlled with hyperglycemia,” on metformin.E11.65 → Z79.84. Not R73.9.
2. Type 2 diabetes on insulin; hypoglycemic episode, no coma; provider documents “level 2 hypoglycemia.”E11.649 → E16.A2 → Z79.4.
3. Type 2 diabetes; hypoglycemia with coma; level not documented.E11.641; no E16.A code, because the note says “if applicable.”
4. No diabetes diagnosis; elevated glucose on labs, provider documents “hyperglycemia.”R73.9 — the diabetes combination code asserts a diabetes diagnosis the record does not contain.

• R73.9 in a diabetic patient — the E10 Excludes1 for hyperglycemia NOS applies; E11.65 is the code.
• E16.2 beside a diabetes code — E16.2 excludes diabetes with hypoglycemia.
• Omitting the E16.A level when the provider documented one, or inventing one when they did not.
• E11.65 from a lab value alone — the provider’s documentation of hyperglycemia or uncontrolled diabetes is what supports the code (Section I.A.19).
• Z79.4 for a temporary insulin course used to correct hyperglycemia during the encounter.

• A diabetes diagnosis — the fork between the E11 codes and R73.9 / E16.2.
• The words “hyperglycemia,” “uncontrolled” or “poorly controlled” from the provider; a glucose value alone is not a diagnosis.
• Coma with the hypoglycemia (E11.641).
• The hypoglycemia level, when the provider states it (E16.A1–A3).
• A drug cause — insulin overdose, missed doses, pump failure — which brings the T38.3X- and, for a pump, T85.6- codes into the sequence.