ICD 10 coding guidelines has many different instructional notes which help us to follow general coding guidelines. For example, the Excludes 1 and Excludes 2 notes which are newly introduced in ICD 10, tells us whether to code these codes together or not. The same way, we have lot of codes in ICD 10 code book which should not be used as primary diagnosis. Manifestation codes are the ones which should not be reported as primary diagnosis. In ICD 10 coding guidelines, we have an instructional note “Code First” with the manifestation codes, which tells to code first the mentioned and then code the manifestation codes. We will go through few ICD 10 codes which are having these instructional notes, so that you become perfect in ICD 10 coding.

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Difference between Code First and Code First Applicable

Since, we are discussing about notes “Code First”, we can come across few ICD 10 codes with instruction notes “Code first, if applicable”. Do not get confused with these two notes, there is a minute difference between these two instructional nodes. In simple terms I will define below notes as:

Code First: Must be used Primary Diagnosis with Manifestation codes

Code First, if Applicable: Can be used as Primary diagnosis. if present.

So, you can easily differentiate between the above two instructional notes. For “Code First, if applicable” note you can code the manifestation code as primary, if any of the mentioned diagnosis in the notes are not present along with the manifestation. While for “Code first” note it is mandatory to use the ICD 10 codes as primary diagnosis mentioned along with the notes.

Examples for “Code First” instruction Note

F02-Dementia in other diseases classified elsewhere
Code first the underlying physiological condition, such as:
Alzheimer’s (G30.-)
cerebral lipidosis (E75.4)
Creutzfeldt-Jakob disease (A81.0-)
dementia with Lewy bodies (G31.83)
epilepsy and recurrent seizures (G40.-)
frontotemporal dementia (G31.09)
hepatolenticular degeneration (E83.0)
human immunodeficiency virus [HIV] disease (B20)
hypercalcemia (E83.52)
hypothyroidism, acquired (E00-E03.-)
intoxications (T36-T65)
Jakob-Creutzfeldt disease (A81.0-)
multiple sclerosis (G35)
neurosyphilis (A52.17)
niacin deficiency [pellagra] (E52)
Parkinson’s disease (G20)
Pick’s disease (G31.01)
polyarteritis nodosa (M30.0)
systemic lupus erythematosus (M32.-)
trypanosomiasis (B56.-, B57.-)
vitamin B deficiency (E53.8)

I43-Cardiomyopathy in diseases classified elsewhere
Code first underlying disease, such as:
amyloidosis (E85.-)
glycogen storage disease (E74.0)
gout (M10.0-)
thyrotoxicosis (E05.0-E05.9-)

H32-Chorioretinal disorders in diseases classified elsewhere
Code first underlying disease, such as:
congenital toxoplasmosis (P37.1)
histoplasmosis (B39.-)
leprosy (A30.-)

G32.0 Subacute combined degeneration of spinal cord in diseases classified elsewhere
Dana-Putnam syndrome
Sclerosis of spinal cord (combined) (dorsolateral) (posterolateral)
Code first underlying disease, such as:
anemia (D51.9)
dietary (D51.3)
pernicious (D51.0)
vitamin B12 deficiency (E53.8)

H62.4O titis externa in other diseases classified elsewhere
Code first underlying disease, such as:
erysipelas (A46)
impetigo (L01.0)

H28 Cataract in diseases classified elsewhere
Code first underlying disease, such as:
hypoparathyroidism (E20.-)
myotonia (G71.1-)
myxedema (E03.-)
protein-calorie malnutrition (E40-E46)