What usually happens next
Read it against the range on your own report.
A mildly raised gap with a normal bicarbonate usually means little; dehydration is a common reason.
What a high anion gap usually means, and its common causes
When an anion gap can read wrong
The anion gap is worked out from sodium, chloride and bicarbonate, so any error in those moves it. Low albumin lowers it (by about 2.5 for each 1 g/dL drop), and labs use different ranges depending on their analyser.
Read it with
Nearby results

Questions
Is an anion gap of 15 mEq/L normal?
An anion gap of 15 mEq/L is above the 4 to 12 mEq/L most modern analysers use, but inside the 8 to 16 older ranges still printed by many labs. The usual range is about 4 to 12 mEq/L on most modern analysers (8 to 16 on older ones); your lab's own range is the one to use.
Is an anion gap of 15 mEq/L bad?
Read it against the range on your report: modern analysers use about 4 to 12 mEq/L, older ones 8 to 16. A high gap with a low bicarbonate matters most.
Worked out by LifeFrom from Kraut and Madias's review and the usual lab ranges, and not yet reviewed by a clinician. For your own understanding: only a lab test, read by your clinician, diagnoses anything.