Healthcare Provider Solutions

Coding Impact on PDGM Grouping Models – Case Mix Groups


As the first year of PDGM has unfolded there have been many twists and turns in the new complexity of coding in home care.

Many of the diagnosis codes we had been utilizing in home health, are no longer allowed as a primary diagnosis, called unacceptable primary diagnoses.

The key to accurate coding under PDGM is to have very specific documentation from your physicians / referral sources!  Ensure that if an unacceptable primary diagnosis is given by the referral / physician, that you ask for the underlying cause – often the underlying cause is an acceptable primary diagnosis.


CMS Expectations for Coding Specificity 


The following are some of the guidelines that CMS spelled out in the November 2018 Federal Register that must be followed for coding under PDGM.

  • Whenever possible, the most specific code that describes a medical disease, condition, or injury should be documented.
    • Generally, ‘‘unspecified’’ codes are used when there is lack of information about location or severity of medical conditions in the medical record.
    • Provider is to use a precise code whenever more specific codes are available.
  • If additional information regarding the diagnosis is needed, the HHA is to follow-up with the referring provider in order to ensure the care plan is sufficient in meeting the needs of the patient.
  • Vague principal diagnosis does not clearly identify the primary reason for home health, and subsequently leads to ambiguous resource use.​
  • A home health clinician should not report an ‘‘unspecified’’ code if that clinician can identify the laterality or site of a condition.
  • Many symptom codes, such as pain or contractures cannot be used as the primary diagnosis: For example,  5, Low back pain or M62.422, Contracture of muscle, right hand, although site specific, do not indicate the cause of the pain or contracture.   In order to appropriately group the home health period, an agency will need a more definitive diagnosis indicating the cause of the pain or contracture, as the reason for the skilled care.
  • R Codes (which are symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified) are not allowed as a primary diagnosis, except for a few dysphagia codes. In the CY 2020 Final Rule, CMS determined that given the current lack of other definitive diagnoses to describe certain forms of dysphagia, the R-codes to describe dysphagia would be acceptable for reporting the primary reason for home health services. Therefore, the following R-codes will be assigned to the Neuro Rehab clinical group:
    • R13.10, R13.11, R13.12, R13.13, R13.14 & R13.19 – Multiple Dysphagia codes
  • CMS recognizes that the coding guidelines allow for the reporting of signs, symptoms, and less well-defined conditions, however, HHAs are required to establish an individualized plan of care in accordance with the home health CoPs at § 484.60.
  • CMS believes that the use of symptoms, signs, and abnormal clinical and laboratory findings would make it difficult to meet the requirements of an individualized plan of care.
    • Clinically it is important for home health clinicians to have a clearer understanding of the patients’ diagnoses in order to safely and effectively furnish home health services.
    • For patient safety and quality of care, it is important for a clinician to investigate the cause of the signs and/or symptoms for which the referral was made.
    • This may involve calling the referring physician to gather more information in order to establish the underlying cause.
  • Muscle weakness is another unacceptable code as a Primary Diagnosis under PDGM. CMS has stated that:
    • M62.81, ‘‘Muscle weakness, generalized’’ is extremely vague.
    • Generalized muscle weakness, while obviously a common condition among recently hospitalized patients does not clearly support a rationale for skilled services and does not lend itself to a comprehensive plan of care.
    • If there is not an identified cause of muscle weakness, then it would be questionable as to whether the course of therapy treatment would be in accordance with accepted professional standards of clinical practice.
    • CMS identified ‘‘muscle weakness (generalized)’’ as a nonspecific condition that represents general symptomatic complaints in the elderly population.
  • S and T codes
  • There are many of the S and T codes where the fracture and/or injury is unspecified, but the site is specified.
    • CMS maintains that the site of injury and/or fracture should be identified; however, the treatment or intervention would likely not change based on the exact type of injury or fracture.
    • Many of these codes are appropriate to group into a clinical group, and are assigned to either the musculoskeletal group or the wounds group.


Ultimately, CMS believes that precise coding allows for more meaningful analysis of home health resource use and ensures that patients are receiving appropriate home health services as identified in an individualized plan of care.  Call us today to get assistance with your home care ICD-10 coding!


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