MCMCB Pro
T80.5

T80.5Anaphylactic reaction due to serum

Non-billable headerICD-10-CM

T80.5 is a non-billable header ICD-10-CM code for anaphylactic reaction due to serum. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

The appropriate 7th character is to be added to each code from category T80

A
initial encounter
D
subsequent encounter
S
sequela

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

  • ABO incompatibility reaction due to transfusion of blood or blood products (T80.3-)
  • allergic reaction or shock NOS (T78.2)
  • anaphylactic reaction or shock NOS (T78.2)
  • anaphylactic reaction or shock due to adverse effect of correct medicinal substance properly administered (T88.6)
  • other serum reaction (T80.6-)

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Allergic shock due to serum
  • Anaphylactic shock due to serum
  • Anaphylactoid reaction due to serum
  • Anaphylaxis due to serum

Other codes that can never be billed with T80.5

These codes carry an Excludes1 note pointing at T80.5. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading T80.5 alone.

  • R57Shock, not elsewhere classified
  • T78.2Anaphylactic shock, unspecified
  • T78.2XXAAnaphylactic shock, unspecified, initial encounter
  • T78.2XXDAnaphylactic shock, unspecified, subsequent encounter
  • T78.2XXSAnaphylactic shock, unspecified, sequela
  • T79.4Traumatic shock
  • T79.4XXATraumatic shock, initial encounter
  • T79.4XXDTraumatic shock, subsequent encounter

Risk adjustment

T80.5 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead T80.5

3 child codes. Green means billable.

Related codes at this level

Codes that share T80. If T80.5 is not quite right, the correct code is usually one of these.

Questions about T80.5

Is T80.5 a billable ICD-10-CM code?
No. T80.5 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does T80.5 sit in the tabular list?
Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Complications of surgical and medical care, not elsewhere classified (T80-T88).
What cannot be coded together with T80.5?
T80.5 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.