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Cystatin C is a serum protein that plays a crucial role in assessing kidney function. It is produced by all nucleated cells in the body and is characterized by its low molecular mass, which enables it to be filtered through the glomerular membrane in the kidneys. When a blood sample is obtained for the measurement of cystatin C levels, it provides valuable information regarding the glomerular filtration rate (GFR). This measurement is particularly significant because, under normal circumstances, cystatin C is filtered out of the blood and subsequently reabsorbed and broken down by the body, without being returned to the bloodstream. However, when kidney function is compromised, the filtration process is impaired, leading to an accumulation of cystatin C in the blood. Elevated levels of cystatin C can indicate decreased kidney function and are utilized in the evaluation of glomerular filtration rate, as well as in the screening and monitoring of renal disease. Additionally, cystatin C levels can serve as a prognostic marker following a heart attack, with higher levels correlating with a poorer survival outlook. The measurement of cystatin C is typically performed using a technique known as nephelometry, which allows for precise quantification of this important biomarker.
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The measurement of cystatin C is indicated for various clinical scenarios, particularly those related to kidney function and overall health assessment. The following conditions and situations warrant the use of cystatin C testing:
The procedure for measuring cystatin C involves several key steps that ensure accurate results. The following outlines the procedural steps:
After the cystatin C measurement procedure, there are generally no specific post-procedure care requirements for the patient. The blood sample collection is minimally invasive, and patients can typically resume their normal activities immediately. However, it is important for healthcare providers to communicate the results to the patient and discuss any necessary follow-up actions based on the cystatin C levels. If elevated levels are detected, further evaluation or monitoring may be warranted to assess kidney function and overall health status.
| Short Descr | CYSTATIN C | Medium Descr | CYSTATIN C | Long Descr | Cystatin C | 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) | No | 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 |
| 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. | 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 | 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. | GV | Attending physician not employed or paid under arrangement by the patient's hospice provider | GW | Service not related to the hospice patient's terminal condition | GC | This service has been performed in part by a resident under the direction of a teaching physician | KX | Requirements specified in the medical policy have been met | 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. | 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. | 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. | 93 | Synchronous telemedicine service rendered via telephone or other real-time interactive audio-only telecommunications system : synchronous telemedicine service is defined as a real-time interaction between a physician or other qualified health care professional and a patient who is located away at a distant site from the physician or other qualified health care professional. the totality of the communication of information exchanged between the physician or other qualified health care professional and the patient during the course of the synchronous telemedicine service must be of an amount and nature that is sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. | AY | Item or service furnished to an esrd patient that is not for the treatment of esrd | 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 | Q3 | Live kidney donor surgery and related services | Q4 | Service for ordering/referring physician qualifies as a service exemption | UA | Medicaid level of care 10, as defined by each state |
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| 2008-01-01 | Added | First appearance in code book in 2008. |
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