Combined ICD10 codes

To code some diagnoses as part of ICD10 collection, several lines of entries in the Patient viewer tab ICD10 need to be grouped together.

To group diagnoses together, use the same Dx Priority for all of them.

Coding instructions

Introduction

• There are numerous situations in which multiple codes need to be listed in order to accurately reflect what's going on medically.
• For some situations the multiple codes need to be linked together (we use the term "combined").
• For other situations it's just a matter of ensuring that the multiple codes are all in the diagnosis list -- i.e. they don't need to be combined.
• For some entities there is no single ICD10 code, and the only way to code the entity is to combine two codes.
  • An example is that to identify Retroperitoneal hemorrhage one must link two codes Hemorrhage, NOS and Retroperitoneal area, diagnostic imaging, abnormal. So, alongside each of those is a message about this.
  • Another example is coding Hospital-acquired pneumonia. To get this you combine Iatrogenic, complication of medical or surgical care NOS with the appropriate type of pneumonia code, e.g. Pneumonia, bacterial or Pneumonia, fungal/yeast

Clinical Situation Plus it's Cause

• Many ICD10 codes are for manifestations of disease, not a specific disorder per se.
• In their Wiki articles it will say something like "also code cause if known" e.g: Hematemesis (upper GI bleed/hemorrhage), NOS
• If the cause is an infection, the Wiki article will instruct to "also code infection source", e.g: Shock, septic
• In general, when you have a manifestation and a cause, the two codes should be combined.

Combined Codes when coding the Primary Admit Diagnosis

Sometimes an entity best represented as a combined code will be the Primary Admit Diagnosis. The way we use these means we don't want a patient to have two. Normal combined coding would lead to two diagnoses with the highest priority so we have to make a choice.

The solution is to do BOTH of the following:

• For the #1, main reason for admission diagnosis, choose as #1 the diagnosis associated with the highest mortality, i.e. the one that’s “worst”. For example, for Liver failure due to Hep B, you'd usually choose the Liver failure as #1.
• ALSO separately code them together, i.e. combined. Yes, there's then some duplication in the diagnosis code list (in the example you'd code Liver failure as the #1 diagnosis, and also code the Liver failure combined with Hep B), but that's OK.

This solution also works for the rare entities which can only be coded with a combination of two codes. The example above of retroperitoneal hemorrhage is a good one if it's the #1 reason for admission. Here you'd code the Hemorrhage, NOS as #1, but ALSO code Hemorrhage, NOS combined with Retroperitoneal area, diagnostic imaging, abnormal

Malignancy with Metastasis

• Here, code BOTH the primary site and the location(s) of mets -- and these need to be combined because the codes for mets don't specify the primary site, only the site of the mets.
• There are codes for mets to the following places:

• If the site of the mets isn't in the list, use Site NOS, metastatic malignancy to it (also code primary site)
• If there are mets to multiple sites, then combine all together the primary malignancy code to the codes for the different sites of the mets.

Infections, Antibiotic Resistance

• There are some single infection codes that incorporate the organism in the name, e.g: Salmonella enteritis
• But for most infections, they don't, e.g: Pneumonia, bacterial
  • In these cases it is required to combine with the infection code the code for the organism from the "buglist":

• The buglist contains specific codes for a number of different bacteria, viruses, fungi/yeast, mycobacteria and miscellaneous types of organisms.
  • If you don't see the specific organism in your case, then there are wastebasket codes:
    • Bacteria, NOS
    • Virus, NOS
    • Fungus or yeast, NOS
    • Nontuberculous mycobacteria
    • and finally when you don't have any idea even what type of bug it is: Infectious disease NOS OR for buglist organism NOS

• NEXT, if the bug is resistant to antimicrobials, the infection/bug combination should be further combined with a code for antibiotic resistance -- thus in this situation there will be 3 or more codes all combined together (the infection, the bug, the antibiotic resistance(s)).

Trauma/injury with mechanism

• There are numerous codes for "mechanical" injuries to various body parts.
• You can recognize these codes because their names include one or another term such as: "injury/trauma" or "traumatic".
• What these have in common is that they are caused by an "external agent" -- such as being hit by a car, falling on your head, etc.
• For these codes, it is required that the injury be combined with the external mechanism of the injury:

• In some cases, the mechanism is actually iatrogenic, see Iatrogenic codes in ICD10.

• Some, but not all fractures fall into the category of trauma/injury. See: Coding fractures in ICD10

Other co-codes

• In addition to the combined coding situations listed above, you can combine codes when it makes sense to you to do so. The general guideline should be that codes be combined (instead of just both listed in the diagnosis list) when they are strongly related to each other.
• Use your judgement. Either listing them separately, or combined ensures that they're all there.

Transition notes

Yes, this different from how we used to use dx priorities where they had to be unique.

Data

The records are combined by same L_ICD10.Dx Priority.