Pathology/Lab Coding Alert

Both compliance and reimbursement can hinge on the correct assignment of ICD-9-CM codes. For Medicare and many other carriers, the diagnosis codes (ICD-9) must conform to the treatment codes (CPT) for the medical services to be reimbursed, says Laurie Castillo, MA, CPC, president of the American Association of Professional Coders, Northern Virginia Chapter and owner of Physician Coding & Compliance Consulting in Manassas, Va. But there seems to be much confusion in the coding community about how to assign the ICD9 Codes when the presenting symptoms or initial diagnosis is different from the definitive diagnosis, she continues. This dilemma is commonplace for pathologists and laboratories because they often provide the definitive diagnosis.

Ever since the Health Care Financing Administration (HCFA) instituted validation edits for ICD-9 codes in 1990, healthcare providers have had to ensure that these codes match the CPT codes to facilitate reimbursement. In this way, Medicare and other carriers are assured that medical treatment is justified by the patients condition.

However, ICD-9 codes cant be conveniently selected to justify a treatment; they have to accurately represent the patients condition and the medical documentation or else they represent fraud, advises Castillo. That comes back to the question of whether to assign ICD-9 codes on the basis of symptoms or diagnosis.

First, you have to realize that the rules are different for outpatient and inpatient services, reports Castillo.

Editor's note: We will cover the guidelines for inpatient services in a future issue of the Pathology Coding Alert.

The directions for these two groups are clearly laid out in the Official ICD-9-CM Guidelines for Coding and Reporting, she continues.

These are the only guidelines that are approved by the cooperating parties for ICD-9-CM: the American Hospital Association, American Health Information Management Association, HCFA and the National Center for Health Statistics, indicates Castillo.

Editors note: These guidelines can be found at www.cdc.gov/nchs/data/icdguide.pdf.

Guidelines for Outpatient Services

The golden rule for outpatient ICD-9 coding is to bill for the reason for the encounter, advises Castillo. If you read the outpatient guidelines, the phrase reason for the encounter/visit appears eight times, and might include diagnoses, symptoms, conditions, problems, complaints or other reasons, she continues. This is one of the main differences between inpatient and outpatient ICD-9 coding. According to the guidelines, outpatient services are to be coded this way, recognizing that diagnoses often are not established at the time of the initial encounter/visit. It may take two or more visits before the diagnosis is confirmed.

Another important rule about outpatient ICD-9 coding is to bill to the highest degree of certainty for that encounter/visit, as stated in section H of the ICD-9 coding guidelines, says Castillo. Other sections of the coding guidelines reinforce this principle; for example, section D directs coders to use codes for symptoms and signs when the physician has not confirmed an established diagnosis.

Under no circumstances should you code outpatient services for a suspected condition as though it actually exits, although this is done for inpatient services, says Castillo. This would include conditions listed in the medical record as probable, possible, rule-out, questionable, and likely.

Trying to report the reason for the encounter and still code to the highest degree of certainty is what seems like a contradiction to many coders, says Castillo, but it isnt. The process simply allows for the fact that, early on, the physician may not know the definitive diagnosis. Thats when the signs and symptoms are coded because that is all that is known. Once the physician knows more about the cause of the symptoms, then the reason for the encounter has become more defined and is coded as a diagnosis.

Sore Throat Provides Spectrum of Examples

Consider three patients who come to the doctor with a sore throat. A quick strep test is conducted for patient A and patient B (CPT code 87880 infectious agent detection by immunoassay with direct optical observation; streptococcus, group A):

Patient As test is positive, so the ICD-9 code would be 034.0 (streptococcal sore throat), which represents the most definitive reason for the encounter that can be given.

Patient Bs strep test is negative, so the ICD-9 code would be 462 (acute pharyngitis), again representing the most definitive reason for the encounter that can be given.

Patient C gets a throat culture rather than a quick strep test. Because the results will not be available for a few days, the physician would report ICD-9 code 462 because it is the most definitive reason for the encounter that can be given.

At the lab, 87060 (culture, bacterial, definitive; throat or nose) would be the correct CPT code for patient Cs culture; depending on the established billing procedure for the lab, one of several ICD-9 codes might be reported. If lab billing is based on ordering physician documentation, ICD-9 code 462 would be reported. But if lab billing is based on the pathologists reports, the ICD-9 code for the causative organism identified by the culture would be reported (e.g., 462 for staphylococcus, 034.0 for streptococcus). In both cases, the ICD-9 code is based on the most definitive reason for the test that can be given at the time.

Notice that the ICD-9 coding is not always based on the presenting symptoms, nor is it always based on the diagnosis, says Castillo. It is always assigned for the most definitive reason that can be given for the encounter, based on what is known at the time.

Although this can lead to some confusion for coders, it actually allows flexibility for different billing systems, she continues. However, because there have been reports of Medicare carriers interpreting these guidelines differently, you should always check with your carrier for clarification, preferably written.

Irregular Vaginal Bleeding Offers Coding Choices

In another example, a 45-year-old patient visits her physician complaining of irregular vaginal bleeding unrelated to her menstrual cycle. Edward J. Wilkinson, MD, FCAP, vice chairman of the department of pathology and laboratory medicine at the University of Florida, Gainesville, suggests that her physician might exam her and order an ultrasound, which would be scheduled at a different location and time. For this initial visit the physician would probably report an evaluation and management (E/M) code, 99201-99215, with ICD-9 code 623.8 (abnormal bleeding from the female genital tract, unspecified) as the most definitive reason for the patient encounter.

The office performing the service would bill for the ultrasound. The ultrasound demonstrates thickening of the endometrium. At this point, there is still no definitive diagnosis, although a little more is known about the condition, says Wilkinson. The physician would report ICD-9 code 621.8 (other specified disorders of uterus, not elsewhere classified) and include the ultrasound documentation in the medical record.

Based on ultrasound findings and clinical history, an endometrial biopsy is carried out in an outpatient setting, says Wilkinson. The surgeon would report the diagnosis code from the referring physician, 621.8, as the reason for the biopsy, 58100 (endometrial sampling [biopsy]).

The pathologist who examines the biopsy would code 88305 (surgical pathology, gross and microscopic examination, endometrium, curettings/biopsy). It is the pathologist who assigns the diagnosis, which in this example is endometrial adenocarcinoma, says Wilkinson. The pathologists claim would list ICD-9 code 182.0 (malignant neoplasm of corpus uteri, except isthmus), as the definitive diagnosis on the basis of the pathologic findings.

Wilkinson continues, From the biopsy, the pathologist reports to the patient's physician the histologic findings and the clinical stage: in this case, stage 1. The physician then determines a treatment plan, and in this case a hysterectomy is performed.

Following the hysterectomy, the pathologist examines the tissue to report histologic grade, tumor type, and depth of invasion of the specimen, says Wilkinson. This reflects the work involved in CPT code 88309 (surgical pathology, gross and microscopic examination; uterus, with or without tubes and ovaries, neoplastic). The diagnosis code reported remains ICD-9 code 182.0.

This example is typical of ICD-9 coding, which is fluid rather than static. For outpatient coding, just remember to code the most definitive reason for the encounter, and to make sure it accurately represents the documentation in the medical record, agree Castillo and Wilkinson.