Pathology/Lab Coding Alert

"Diagnosis coding for laboratory work can often prove challenging for pathology coders. Questions arise about whether the ICD9 Codes should be assigned based on test results or the reason for the test, whether screening or signs and symptoms prompted the test. There is also debate about who should assign the ICD-9 code the requesting physician or the laboratory coder.

Because correct diagnosis codes are the key to adequate reimbursement for lab-oratory tests, the treating physician must provide at least a narrative description of the reason for the test, and the ICD-9 code should be assigned to the highest degree of certainty available at the time of billing.

It is difficult for coders to know what to do because there is conflicting information in writing, says Barbara J. Cobuzzi, CPC, MBA, CHBME, president of Cash Flow Solutions Inc., a physician practice billing company in Lakewood, N.J.

Assigning the correct diagnosis code for tests and laboratory work is particularly important because Medicare doesnt cover preventive screening or services in most cases, Cobuzzi says. Items and services not deemed reasonable and necessary for the diagnosis or treatment of illness or injury, or to improve the functioning of a malformed body member, are excluded under Medicare Part A and Part B. That means coders must understand when a test is not a screening, and how proper diagnosis coding can affect appropriate reimbursement.

Screenings are usually performed during annual exams, Cobuzzi says. The patient comes into the office with no problems or complaints, and the physician runs some tests to make sure there are no underlying illnesses that are being missed. The physician and the patient didnt think anything was wrong when the test was ordered, and if nothing is wrong, the screening code is used. Paradoxically, if the test uncovered a medical problem, the diagnosis code for the problem would justify the medical necessity of the test, Cobuzzi says. However, other people would disagree with this interpretation and claim that if the test was ordered for screening, that the screening code must be used.

What about the instance of a patient who presents with an unknown problem, and tests are ordered to help determine the cause of the complaint? The diagnosis should reflect the presenting signs and symptoms rather than a screening code. The test is considered diagnostic rather than screening even though no illness is found, Cobuzzi stresses. The patients subjective complaint is sometimes the only thing you have. Its the reason the patient came to you and the reason the test was ordered.

Diagnosis Coding When Test Is Negative

Actually, assigning a diagnosis code when the test is ordered and comes back negative is not as controversial as when the test comes back positive for the suspected problem, Cobuzzi says.

If it is a screening test (meaning there are no signs or symptoms or a chief complaint) and the test comes back negative, use a code for a screening such as V76.44 (special screening for malignant neoplasms, prostate). If the patient has signs and symptoms and the test is negative, I recommend coding the signs and symptoms, Cobuzzi says.

For example, a patient presents to the physician complaining of frequent severe thirst and episodes of weakness. The physician orders a comprehensive metabolic panel (80053) to detect or rule out diabetes (250.xx) or kidney disorders. In the section for diagnostic information on the form sent to the lab, the physician lists 783.5 (polydipsia, excessive thirst) and 780.79 (other malaise and fatigue, asthenia NOS).

According to the Medicare Carriers Manual (MCM) section 4020.3, (available at www.hcfa.gov/pubforms /14_car/3b4010.htm#_1_10), the physician should assign a diagnosis code(s) from 001.0 through V82.9 to identify diagnoses, symptoms, conditions, problems, complaints, or other reason(s) for the encounter/visit.

In the above example, even if the metabolic panel tests are negative for diabetes or kidney disorders, report the ICD-9 codes for the symptoms that prompted the physician to order the tests.

Also, the MCM states, Do not code diagnoses documented as probable, suspected, questionable or rule out as if they are established. Rather, code the condition(s) to the highest degree of certainty for that encounter/visit, such as symptoms, signs, abnormal test results or other reasons for the test.

If the codes for the signs or symptoms do not get the claim paid in this instance, there is generally nothing else for the biller to do. The symptoms were the reason for the tests, but no disease was found. If payment is denied, the physician can appeal and resubmit with documentation of the visit.

Coding When Final Diagnosis Is More Specific

But, what if the tests had come back positive for diabetes, i.e., 250.00 (diabetes mellitus without mention of complication, type II [non-insulin dependent type] [adult- onset type] or unspecified type, not stated as uncontrolled)? Should the ICD-9 used on the claim be the final diagnosis (more specific) or the presenting signs and symptoms (reason the test was performed)?

Using the code that indicates the final diagnosis when it is a more specific illness is the choice most coders make. If the test gives a more specific result, I would recommend using that, Cobuzzi says. However, many people disagree with that.

In contrast to the above citations from the MCM, other written documentation supports using the final diagnosis when applicable.

According to the Official ICD-9-CM Guidelines for Coding and Reporting (available at www.cdc.gov/nchs/ data/icdguide.pdf) coders are to report to the highest degree of certainty for the encounter/visit. These are the only guidelines that are approved by the cooperating parties for ICD-9: the American Hospital Association, American Health Information Management Association, HCFA and the National Center for Health Statistics.

The guidelines further direct coders to use codes for symptoms and signs when an established diagnosis has not been confirmed by the physician, implying that the established diagnosis is used once it is confirmed. In an example, the guidelines explain, If the postoperative diagnosis is different from the preoperative diagnosis select the postoperative diagnosis for coding, since it is the most definitive.

Other documentation for coding the diagnosis comes from the MCM in an example for patients receiving only ancillary diagnostic services during an encounter or visit: V72.6 (laboratory examination) will describe the reason for the encounter (e.g., study biopsy specimen). If at the time of the bill submittal, there is a diagnosis (e.g., malignant neoplasm) then an additional code can be submitted to describe the diagnosis.

Document Medical Necessity

Physicians need to know the proper way to document the medical necessity of the work they do. And laboratories need to ensure that they receive the appropriate documentation from the treating physician regarding the ordered tests. Laboratories can do this by gathering the information on requisition forms.

Laboratory requisition forms should be designed to capture the correct information to promote appropriate ordering of tests, says Thomas Kent, CMM, president of Kent Medical Management, a coding and practice management firm in Dunkirk, Md. For example, when ordering a Pap smear, the form should prompt the treating physician to designate whether it is a diagnostic test (such as 88142, cytopathology, cervical or vaginal [any reporting system], collected in preservative fluid, automated thin layer preparation; manual screening under physician supervision) or screening test (such as P3000, screening Papanicolaou smear, cervical or vaginal, up to three smears, by technician under physician supervision) and inform the physician of the frequency constraints for screening tests. The requisition should also require the physician to submit diagnosis information as documentation of medical necessity, Kent says.

If the treating physician doesnt accurately record the reason for the test, whether that be screening, presenting signs and symptoms, or known medical condition, the coder cannot apply the correct diagnosis code. The laboratory cannot assign a code if the physician does not supply appropriate documentation in the medical record.

A vague sign or symptom is a perfectly acceptable reason for a test. Physicians need to know that its OK to write down abdominal pain (789.0x, abdominal pain) as a diagnosis because they dont know if the patient has gastroenteritis, colitis or appendicitis before performing the diagnostic tests, Cobuzzi says.

Many payers, most notably Medicare carriers, have specific lists of covered diagnoses for each laboratory or diagnostic test and procedure. The procedure or test is covered only if one of the diagnosis codes on the list is used. Medicare carriers distribute these coverage rules in their local medical review policies (LMRPs). Coders must be familiar with these local rules as well as any national Medicare policies concerning covered diagnoses for specific lab tests. Many local rules can be viewed at www.lmrp.net.

Because of Medicares requirement for substantiating medical necessity, the use of advanced beneficiary notices (ABNs) is crucial to ensure reimbursement for laboratory tests, Cobuzzi says. If neither the signs and symptoms nor the test results demonstrate medical necessity, the laboratory cannot bill the patient for the test unless they have a signed ABN from the patient. Remember, even with a payable diagnosis, the test may exceed the frequency limitations set by Medicare, making an ABN essential to protect the labs reimbursement.

The Physicians Role in Assigning Diagnosis Codes

For the most specific ICD-9 codes to be applied, many physicians just write a phrase indicating the reason for the lab test and allow the laboratory to apply the ICD-9 codes before the claim is sent to the payer. The MCM states, Ordering physicians are not required to include diagnosis codes on referral slips or requests for diagnostic tests. However, consistent with accepted medical practice, such referral slips or requests should include a narrative description of the reason for the test. In addition to assisting the radiologist, pathologist or other physician in the proper performance and interpretation of the requested test, the information will assist the referring physician in the completion of his or her bill or claim for payment.

Note, however, that the 1997 Balanced Budget amendment included the following paragraph: The physician or practitioner will be required to provide the diagnostic information to the entity [e.g., the lab-oratory] at the time the service is ordered by the physician or practitioner.

HCFAs proposed rule for clinical diagnostic laboratory services (March 10, 2000, Federal Register) states, Laboratories that receive narrative diagnosis information from an ordering physician must translate that information into an appropriate diagnosis code (ICD-9-CM code) to submit the claim electronically. An appropriate diagnosis code may be assigned to a narrative, even if the wording ... does not exactly match the code descriptor. It then states, If an ICD-9-CM code is submitted by the ordering physician, laboratories must use that code in submitting the claim unless the laboratory has obtained documentation from the physician to support altering the code."