ICD-9 CM & ICD-10 CM CODING OF DRUGS, MEDICAMENTS AND BIOLOGICAL SUBSTANCES

One of the major changes seen in the structure and organization of ICD-10 CM is in the

classification of Poisonings and Adverse Effect of Drugs, Medicaments and Biological

Substances, categories T36-T50. These categories are located in Chapter 19: Injury, Poisoning,

and Certain Other Consequences of External Causes (S00-T88) in ICD-10 CM. They are found

in Chapter 17: Injury and Poisoning (800-999) in the categories 960-979 for a current condition

in ICD-9 CM. In ICD-10 CM, some of the categories in Chapter 19 call for a 7th

character to

complete the code. Categories T36-T50 must meet this requirement. The 7th

characters should

be one of three below:

A=Initial Encounter. This encounter is the first time the patient is seen for the condition. It does

not matter when the treatment is administered as long as it is the first time treatment is being

administered.

B=Subsequent Encounter. This encounter is for any treatment received after the initial encounter

for treatment. The treatment is given during what is considered the recuperation period and is

often termed as a “follow-up visit.”

C=Sequela. This encounter is for the treatment of conditions that are a result of a condition.

The code for the injury with the 7th

character “S” and the code for the sequela are both coded.

The coder is to pay particular attention to the sequencing in this case. The sequela is sequenced

first.

ICD-9 CM codes do not have a 7th

character “S” requirement. They do, however, have a

late effect code, 909.0 Late Effect of Poisoning due to Drug, Medicinal, or Biological Substance

or 909.5 Late Effect of Adverse Effect of Drug, Medical or Biological Substance. For

subsequent (follow-up) visits an appropriate “V” code is used followed by the appropriate

poisoning code for further specificity. Another difference between the two nomenclatures is that

ICD-10 CM codes do not have supplemental codes to describe the circumstances surrounding the

nature of the poisoning. Each drug category has a code for accidental, intentional, assault,

undetermined, and adverse effect (which is therapeutic use in ICD-9 CM). In both ICD-9 CM

and ICD-10 CM, codes would be used expressing the result of the adverse effect; unless the

result of the adverse effect is unknown. Then the coder would use codes 995.20 or 995.29 in

ICD-9 CM in conjunction with the applicable codes from the Supplementary Classification of

External Causes of Injury and Poisoning (E000-E999) category. Codes T50.905 (7th

character A,

D, or S) or T50.906 (7th

character A, D, or S) would be applied in ICD-10 CM. Lastly, the ICD-

10 CM code set has codes for “Underdosing” which is not the case in ICD-9 CM. Let’s look at

comparison coding for poisoning of the drug Digoxin in a patient who is being treated for the

first time.

DIGOXIN POISONING

As stated previously, the adverse effect of Digoxin would require that the coder know the nature

of the adverse effect (i.e., tachycardia, vomiting) and this would be coded in both ICD-9CM and

ICD-10 CM. In ICD-9 CM, the code would be followed by the code E942.1. In ICD-10 CM,

the code would be followed by T46.05XA.

Finally, Underdosing is referred to as taking less of a prescribed drug. ICD-9 CM does not have

a specific code for Underdosing. The coder must code the manifestation of the Underdosing,

such as an exacerbation of the condition for which the drug is being taken. In ICD-10, the

exacerbated condition and T46.06XA should be coded.

NOTE: In ICD-10 CM, the Underdosing code should not be used as the principal

diagnosis. It is considered a secondary code. The condition that results from the

Underdosing should be the principle diagnosis.

NOTE: Codes stating the intent, if known of the Underdosing should also be coded.

Accidental •ICD-9 (972.1 & E858.3)

•ICD-10 (T46.01XA)

Intentional •ICD-9 (972.1 & E950.4)

•ICD-10 (T46.02XA)

Assault •ICD-9 (972.1 & E962.0)

•ICD-10 (T46.03XA)

Undetermined

•ICD-9 (972.1 & E980.4)

•ICD-10 (T46.04XA)

Cynthia Brown, MBA, RHIT, CCS AHIMA Approved ICD-10 CM/PCS Trainer CyntCoding Health Information Services Phone: 404-992-8984/E-Fax: 678-805-4919 P.O. Box 3019 Decatur, GA 30031 cyntcoder@cyntcodinghealthinformationservices.com www.cyntcodinghealthinformationservices.com http://cyntcodinghealthinformationservices.blogspot.com Coding Yesterday’s Nomenclature Today®

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