I was reading this paper
and from this paper I quote
Restrict the labels to the most common Level 5 codes, method used by some project reports.7 We start by selecting the 20 most common codes (see Figure 2)
Can someone explain to me what are the 5 levels?
When I look at ICD9 I can see these 4 Levels only
Level 1 :
I 001–139 Infectious and Parasitic Diseases II 140–239 Neoplasms III 240–279 Endocrine, Nutritional and Metabolic Diseases, and Immunity Disorders IV 280–289 Diseases of the Blood and Blood-forming Organs V 290–319 Mental Disorders VI 320–389 Diseases of the Nervous System and Sense Organs VII 390–459 Diseases of the Circulatory System VIII 460–519 Diseases of the Respiratory System IX 520–579 Diseases of the Digestive System X 580–629 Diseases of the Genitourinary System XI 630–679 Complications of Pregnancy, Childbirth, and the Puerperium XII 680–709 Diseases of the Skin and Subcutaneous Tissue XIII 710–739 Diseases of the Musculoskeletal System and Connective Tissue XIV 740–759 Congenital Anomalies XV 760–779 Certain Conditions originating in the Perinatal Period XVI 780–799 Symptoms, Signs and Ill-defined Conditions XVII 800–999 Injury and Poisoning
Level 2 :
583 Nephritis and nephropathy, 596 Other disorders of bladder
Level 3 :
596.0 Bladder neck obstruction 596.4 Atony of bladder 596.5 Other functional disorders of bladder
Level 4 :
596.51 Bladder hypertonicity 596.52 Bladder compliance, low 596.54 Neurogenic bladder, NOS 596.55 Detrusor sphincter dyssynergia
So where is the 5th level?