Can you Screen for an Existing Condition? | Diagnosis Coding for Lab Services

Sometimes, the hardest thing about coding for preventive services isn’t the visit at all. It’s the labs.

Patients come in for an annual physical and many times they believe that all of the lab work done that day or in preparation for that day will be covered as part of their preventive service. And we know what that means to patients.  They hope it means no co-pay, no-coinsurance, no deductible. In a word: no patient due balance.

But, that’s not always the case. If the patient has a condition, then labs to monitor that condition are not considered screening.

Screening at the time of a preventive service

When billing for laboratory tests medical practices need to follow ICD-10 rules, and Medicare and other payer regulations.  When thinking about diagnosis coding, it’s always smart to start with the official guidelines for ICD-10-CM coding.  These are found at the start of the book, or can be downloaded from the CDC website  in PDF form. https://www.cdc.gov/nchs/data/icd/10cmguidelines-FY2022-7-2022-508.pdf

From ICD-10:

Screening is the testing for disease or disease precursors in seemingly well individuals so that early detection and treatment can be provided for those who test positive for the disease (e.g., screening mammogram).

Notice that the guidelines say a screening is a test performed on a patient who is well, for the purpose of the early detection. A patient who has already been diagnosed with a condition cannot be screened for that condition.

A patient with high cholesterol on her problem list whose lipids are monitored is not being screened.   She is receiving a test to monitor an existing condition. It would be incorrect to use the diagnosis code of screening when the patient has the previously diagnosed condition.

Questions | Test your coding knowledge

What diagnosis code would you use for a patient with no known lipid disease, for a lipid test ordered at a preventive service?

Z13.220, encounter for screening for lipoid disorder.

What diagnosis code would you use for a patient with documented high cholesterol who had their labs ordered at a preventive medicine service?

A code from category E78, disorders of lipoprotein metabolism and other lipidemias.  The patient already has the condition, so monitoring it is not considered screening.

Testing for a sign or symptom

From ICD-10:

On the other hand, a patient comes in with a complaint for symptoms and needs a diagnostic test, is coded with the sign or symptom that is the reason for the test. That is not considered screening.

Testing to rule out or confirm a suspected diagnosis because the patient has a sign or symptom is a diagnostic examination, not a screening.

In these cases, the sign or symptom is used to explain the reason for the test.  A patient comes in complaining of fatigue and the physician notes that the patient is pale and orders a blood test.  Use fatigue and pallor for the diagnosis codes.

Code for screening

There is a general code for screening, Z01.89, described in the ICD-10 guidelines, below.

There are also more specific codes for screening that are required by Medicare and other payers for specific tests and conditions.

For example, if ordering a mammogram for screening, use Z12.31 encounter for screening for malignant neoplasm of the breast.

From ICD-10:

For encounters for routine laboratory/radiology testing in the absence of any signs, symptoms, or associated diagnosis, assign Z01.89, Encounter for other specified special examinations. If routine testing is performed during the same encounter as a test to evaluate a sign, symptom, or diagnosis, it is appropriate to assign both the Z code and the code describing the reason for the non-routine test.

Check your payer’s medical policies and CMS’s preventive guide.

In addition to the correct CPT^® codes that are covered for what indications (diagnosis codes) there are frequency limitations described.

If you have your ICD-10 book handy, look at Section IV Diagnostic Coding and Reporting Guidelines for Outpatient Services, K. Patients receiving diagnostic services only.

Diagnosis coding after interpretation by a physician

From ICD-10:

For outpatient encounters for diagnostic tests that have been interpreted by a physician, and the final report is available at the time of coding, code any confirmed or definitive diagnosis(es) documented in the interpretation. Do not code related signs and symptoms as additional diagnoses.

Please note: This differs from the coding practice in the hospital inpatient setting regarding abnormal findings on test results.

One of the difficulties in coding is that there are different rules for professional services and facility services.

This ICD-10 guidance tells us that if the test has been interpreted by a physician, and that final report is available when the code for the test is being submitted, use the confirmed/definitive diagnosis, not the sign or symptom. The ICD-10 “please note” notation reminds us that this rule is not the same as the hospital inpatient setting rules.

Patient complaints | Coding for lab services

Who has received this call or one like it?  “You’ve coded that lab test wrong.  The insurance company says if you just change the code, they’ll pay it.”

• Use a sign, symptom or diagnosis when the test is being done to monitor an existing disease or condition or to diagnosis a condition, based on a symptom.
• Use a screening diagnosis for tests ordered “in the absence of any signs, symptoms or associated diagnosis.” Associated diagnosis is the condition being treated.

More about diagnosis coding and preventive medicine services

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Relevant Search Terms: ICD-10 for screening; diagnosis coding for labs; labs and preventive services; Medical practice coding for screening tests; LCDs; payer medical policies for screening