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The CPT® Code 84520 refers to the quantitative measurement of urea nitrogen in the blood, commonly known as Blood Urea Nitrogen (BUN). This procedure involves obtaining a blood sample to determine the total level of urea nitrogen present. Urea is a waste product that is generated in the liver through a series of biochemical reactions known as the urea cycle, or Krebs-Henseleit cycle, which is primarily responsible for the metabolism of proteins. Once produced, urea enters the bloodstream and is subsequently filtered by the kidneys, where it is excreted in the urine. The measurement of BUN is crucial for assessing renal function, as it provides valuable insights into the kidneys' ability to filter waste from the blood. Additionally, BUN levels are monitored in patients with existing renal disease to evaluate the progression of their condition and the effectiveness of treatments such as dialysis. Furthermore, BUN may be assessed in individuals suffering from acute or chronic illnesses that could potentially impact renal function, making it an important diagnostic tool in various clinical scenarios. The quantification of BUN is typically performed using a laboratory technique called spectrophotometry, which allows for accurate measurement of the urea nitrogen concentration in the blood sample.
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The quantitative measurement of urea nitrogen (BUN) is indicated for several clinical scenarios, particularly those related to renal function and overall metabolic health. The following conditions and situations warrant the performance of this procedure:
The procedure for measuring blood urea nitrogen (BUN) involves several key steps that ensure accurate results. The following outlines the procedural steps involved:
After the blood sample has been collected for BUN measurement, there are generally no specific post-procedure care requirements for the patient. However, patients may be advised to drink plenty of fluids to help maintain hydration, especially if they are fasting prior to the test. The results of the BUN test will typically be available within a few hours to a day, depending on the laboratory's processing time. Healthcare providers will discuss the results with the patient, and if necessary, further diagnostic tests or treatments may be recommended based on the findings.
| Short Descr | ASSAY OF UREA NITROGEN | Medium Descr | ASSAY OF UREA NITROGEN QUANTITATIVE | Long Descr | Urea nitrogen; quantitative | Status Code | Statutory Exclusion (from MPFS, may be paid under other methodologies) | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 9 - Not Applicable | Multiple Procedures (51) | 9 - Concept does not apply. | Bilateral Surgery (50) | 9 - Concept does not apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 9 - Concept does not apply. | Co-Surgeons (62) | 9 - Concept does not apply. | Team Surgery (66) | 9 - Concept does not apply. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | CLIA Waived (QW) | Yes | APC Status Indicator | Conditionally packaged laboratory tests | Type of Service (TOS) | 5 - Diagnostic Laboratory | Berenson-Eggers TOS (BETOS) | T1H - Lab tests - other (non-Medicare fee schedule) | MUE | 1 | CCS Clinical Classification | 233 - Laboratory - Chemistry and Hematology |
| QW | Clia waived test | 90 | Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number. | 91 | Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient. | AY | Item or service furnished to an esrd patient that is not for the treatment of esrd | Q1 | Routine clinical service provided in a clinical research study that is in an approved clinical research study | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | 26 | Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number. | Q4 | Service for ordering/referring physician qualifies as a service exemption | XS | Separate structure, a service that is distinct because it was performed on a separate organ/structure | GA | Waiver of liability statement issued as required by payer policy, individual case | GZ | Item or service expected to be denied as not reasonable and necessary | GW | Service not related to the hospice patient's terminal condition | Q6 | Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area | GV | Attending physician not employed or paid under arrangement by the patient's hospice provider | XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service | 77 | Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service. | CR | Catastrophe/disaster related | GY | Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit | PD | Diagnostic or related non diagnostic item or service provided in a wholly owned or operated entity to a patient who is admitted as an inpatient within 3 days | Q0 | Investigational clinical service provided in a clinical research study that is in an approved clinical research study | Q3 | Live kidney donor surgery and related services | QJ | Services/items provided to a prisoner or patient in state or local custody, however the state or local government, as applicable, meets the requirements in 42 cfr 411.4 (b) | X1 | Continuous/broad services: for reporting services by clinicians, who provide the principal care for a patient, with no planned endpoint of the relationship; services in this category represent comprehensive care, dealing with the entire scope of patient problems, either directly or in a care coordination role; reporting clinician service examples include, but are not limited to: primary care, and clinicians providing comprehensive care to patients in addition to specialty care | XE | Separate encounter, a service that is distinct because it occurred during a separate encounter |
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| 2013-01-01 | Changed | Medium Descriptor changed. |
| Pre-1990 | Added | Code added. |
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