To summarize policy translation using the GEMs so far:
Phase 1: Use the 10-to-9 singles GEM with reverse lookup to find all the ICD-10 codes that select patients currently selected by the ICD-9 codes in the policy.
Phase 2: For any unused ICD-9 codes, use the 9-to-10 singles GEMs to find other ICD-10 codes which may, after clinical review, be worth including
Phase 3: Look up all the ICD-9 codes in the 10-to-9 cluster GEM with reverse lookup. ICD-10 codes you find there will have a narrower definition than the ICD-9 code you find them with, so you must review them to ensure they contribute to the intent of your policy.
There may still be some ICD-9 codes on your list that haven’t been accounted for. The GEMs has a translation for every ICD-9 code and for every ICD-10 code (despite what you might have heard elsewhere) so those unused ICD-9 codes must be somewhere. Since they were not in either of the GEMs single-code translation tables, they must be in the GEMs cluster tables (which we set aside in Part 7). Consequently, we explored clusters in Part 10.
The final step in translation is to look up each unused ICD-9 policy code in the 9-to-10 GEMs cluster table. If you find the code there you will find it on several lines, and on each line there will be a scenario number, a choices number, and an ICD-10 code. We’ll use an example to help explain what scenario and choices are for.
415.11 Iatrogenic pulmonary embolism and infarction
Here is how CTT displays its GEM translation to an ICD-10 cluster:
T80.0XXA Air embolism following infusion, transfusion and therapeutic injection, initial encounter
T81.718A Complication of other artery following a procedure, not elsewhere classified, initial encounter
T81.72XA Complication of vein following a procedure, not elsewhere classified, initial encounter
T82.817A Embolism of cardiac prosthetic devices, implants and grafts, initial encounter
T82.818A Embolism of vascular prosthetic devices, implants and grafts, initial encounter
With one of
I26.90 Septic pulmonary embolism without acute cor pulmonale
I26.99 Other pulmonary embolism without acute cor pulmonale
The ICD-9 code 415.11 is represented in ICD-10 by two codes, one for the iatrogenic event and the other for the pulmonary embolism. However, given the lack of specificity in the ICD-9 code, there are five different ICD-10 codes that could represent the iatrogenic event (depending on information in the patient’s record which we do not have, but a coder would) and two different ICD-9 codes that may represent the pulmonary embolism (ditto). In effect, there are ten different two-code clusters that 415.11 might appear as in ICD-10: T80.0XXA+I26.90, T81.718A+I26.90, T81.72XA+I26.90, T82.817A+I26.90, T82.818A+I26.90, T80.0XXA+I26.99, T81.718A+I26.99, T81.72XA+I26.99, T82.817A+I26.99, and T82.818A+I26.99.
Rather than spell out all combinations, the GEMs uses the “Chinese restaurant menu” representation: in this example, one of five from column A with one of two from column B. The choices column in the GEM table tells numerically which set of choices each code belongs with. The GEMs table for 415.11 will therefore look like this (with flags removed for readability):
41511 1 1 T800XXA
41511 1 1 T81718A
41511 1 1 T8172XA
41511 1 1 T82817A
41511 1 1 T828181A
41511 1 2 I2690
41511 1 2 I2600
What about scenario? Consider this example:
806.00 Closed fracture of C1-C4 level with unspecified spinal cord injury
for which the GEMs provides four alternative translations, all clusters. Here are the first two:
S14.101A Unspecified injury at C1 level of cervical spinal cord, initial encounter
With one of
S12.000A Unspecified displaced fracture of first cervical vertebra, initial encounter for closed fracture
S12.001A Unspecified nondisplaced fracture of first cervical vertebra, initial encounter for closed fracture
S14.102A Unspecified injury at C2 level of cervical spinal cord, initial encounter
With one of
S12.100A Unspecified displaced fracture of second cervical vertebra, initial encounter for closed fracture
S12.101A Unspecified nondisplaced fracture of second cervical vertebra, initial encounter for closed fracture
The GEMs cannot munge all these together into one Chinese menu, because the spinal cord injury to C1 shouldn’t go with the C2 fracture, etc. So each cluster alternative is given a different scenario number: The C1 vertebra cluster is scenario 1, the C2 cluster is scenario 2, and so on. 806.00 thus appears (again with flags removed):
80600 1 1 S14101A
80600 1 2 S12000A
80600 1 2 S12001A
80600 2 1 S14102A
80600 2 2 S12100A
80600 2 2 S12101A
80600 3 1 S14103A
80600 3 2 S12200A
80600 3 2 S12201A
80600 4 1 S14104A
80600 4 2 S12300A
80600 4 2 S12301A
Now that we’ve learned how to read clusters in the GEMs, we can talk about what to do with them. We’ll take that up in Part 13.
Ron Mills is a Software Developer for the Clinical & Economic Research department of 3M Health Information Systems.
You can find the complete DIY ICD-10 series here.