ICD-10-CM > G00-G99 > G89-G99 > G93 > G93.3 G93.3 Postviral and related fatigue syndromes Non-Billable/Non-Specific Use Additional code, if applicable, for post COVID-19 condition, unspecified (U09.9) Type 1 Excludes chronic fatigue NOS (R53.82)neurasthenia (F48.8) Codes G93.31Postviral fatigue syndromeG93.32Myalgic encephalomyelitis/chronic fatigue syndromeG93.39Other post infection and related fatigue syndromes