Basics of DRG codes

DRG codes are used in Inpatient coding. There are many factors which affects DRG codes and this directly affect the reimbursement. Since each DRG code has particular dollar value, any change in the DRG will lead to change in the dollar value and there will be change in the payment amount as well.

Today we will see how the diagnosis codes affects the DRG codes and also see the importance of CC and MCC codes on these codes.

Selection of DRG codes

DRG codes will be reflected automatically in 3M once you will start adding the ICD-10 codes for inpatient coding. Also you will see the MDC category code as well as shown below. MDC category consist of different DRG codes based on with/without MCC/CC. Below are the list of MDC.

Pre-MDC
MDC 01 Diseases and disorders of the nervous system
MDC 02 Diseases and disorders of the eye
MDC 03 Diseases and disorders of the ear, nose, mouth and throat
MDC 04 Diseases and disorders of the respiratory system
MDC 05 Diseases and disorders of the circulatory system
MDC 06 Diseases and disorders of the digestive system
MDC 07 Diseases and disorders of the hepatobiliary system and pancreas
MDC 08 Diseases and disorders of the musculoskeletal system and connective tissue
MDC 09 Diseases and disorders of the skin, subcutaneous tissue and breast
MDC 10 Endocrine, nutritional and metabolic diseases and disorders
MDC 11 Diseases and disorders of the kidney and urinary tract
MDC 12 Diseases and disorders of the male reproductive system
MDC 13 Diseases and disorders of the female reproductive system
MDC 14 Pregnancy, childbirth and the puerperium
MDC 15 Newborns and other neonates with conditions originating in perinatal period
MDC 16 Diseases and disorders of blood, blood forming organs and immunologic disorders
MDC 17 Myeloproliferative diseases and disorders, poorly differentiated neoplasms
MDC 18 Infectious and parasitic diseases, systemic or unspecified sites
MDC 19 Mental diseases and disorders
MDC 20 Alcohol or drug use or induced organic mental disorders
MDC 21 Injuries, poisonings and toxic effects of drugs
MDC 22 Burns
MDC 23 Factors influencing health status and other contacts with health services
MDC 24 Multiple significant trauma
MDC 25 Human immunodeficiency virus infections

Now, in below example we have admit and principal diagnosis as dysuria (R30.0). Below you can see the estimated reimbursement as $3553, when it is the only diagnosis coded.

DRG codes reflected as 696 (Kidney and urinary tract signs and symptoms without MCC) and MDC code as 011. The description for both are also given in below image.

Effect of CC on DRG code 696

Here, when we tried to add a CC (Complication and Comorbidity) code N17.9 for Acute kidney failure, unspecified, we can see there is no change in the DRG. The DRG still remain to 696. This happens because the DRG code description says “Kidney and urinary tract signs and symptoms without MCC”.

Since the primary diagnosis is R30.0 (dysuria) which is a symptom, so the DRG code support this ICD 10 diagnosis code. But if we change the primary diagnosis to severe disease or disorder related to kidney or urinary tract then DRG code will surely change and their will change in the reimbursement amount as well. Let us check in the next image.

Note: MCC and CC are list of codes that are defined as either a complication or comorbidity (CC) or a major complication or comorbidity (MCC) when used as a secondary diagnosis.

Effect of MCC on DRG code

Now, when we add a MCC (Major Complication and Comorbidity) code n18.6 (end stage renal disease) the DRG code changes to 695 ““Kidney and urinary tract signs and symptoms with MCC”. This is because of the presence of MCC code N18.6.

Also there is increase in the reimbursement amount to $5150. This shows why MCC code should not be missed in inpatient coding, because patient with N18.6 will surely need lot of attention from provider and this surely increase their payment.

Diagnosis sequence effect of DRG code

Now, when we change the ESRD code N18.6 from secondary to primary diagnosis position the DRG code changes to 684 “Renal failure without CC/MCC”. Now, here N18.6 as Principal diagnoses a CC/MCC code get converted to non-CC. So code N18.6  a non-CC code here in this scenario.

Also, remember CC and MCC codes qualify only when coded as secondary diagnosis.

Also the reimbursement amount changed to $3243, just ESRD N18.9 is coded as primary diagnosis. The decrease in reimbursement because there is no CC or MCC code in this scenario, so abviously the reimbursement amount will less.

Hope, now you would have understood how the DRG code changes and the effect of CC and MCC position changes the reimbursement in inpatient coding.