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Molecular genetic testing, specifically chimerism analysis, is a critical procedure performed to assess the extent of chimerism following hematopoietic stem cell transplantation. This analysis involves the identification of genetic profiles from both the donor and the recipient, allowing for a comprehensive evaluation of the proliferation of donor cells within the recipient's blood, bone marrow, or other tissues. The term "chimerism" refers to the presence of two genetically distinct cell lines within an individual, which can occur post-transplantation. It is important to note that while complete conversion to donor cells is a possible outcome, the presence of both donor and recipient cells does not necessarily indicate graft failure. The testing process utilizes genomic polymorphisms known as short tandem repeat (STR) loci, which consist of repeated core DNA sequences located at specific gene loci. These sequences contain information within their flanking regions, which are essential for creating oligonucleotide primer pairs used in the testing process. The polymerase chain reaction (PCR) amplification technique is employed to amplify the DNA samples, followed by separation of the strands through methods such as electrophoresis gel or capillary electrophoresis (CE). This PCR-based STR/CE method is particularly advantageous as it allows for the simultaneous testing of multiple DNA strands using minimal sample sizes. Additionally, this technique has demonstrated effectiveness in various applications, including the analysis of graft failure, severe leukopenia, hematopoietic cell subset fractions, double cord blood donor units, and cases involving a second transplant from a different donor.
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The chimerism (engraftment) analysis is indicated for the following conditions:
The procedure for chimerism analysis involves several key steps that ensure accurate assessment of donor and recipient cell populations:
After the chimerism analysis is completed, the results are typically reviewed by the healthcare provider to assess the engraftment status of the transplant. The findings can guide further clinical decisions, including the need for additional monitoring or interventions. Patients may be advised on follow-up appointments to discuss the results and any necessary next steps in their treatment plan. It is essential to consider that the interpretation of chimerism results should be done in conjunction with clinical findings and other laboratory tests to provide a comprehensive understanding of the patient's post-transplant status.
| Short Descr | CHIMERISM ANAL NO CELL SELEC | Medium Descr | CHIMERISM W/COMP TO BASELINE W/O CELL SELECTION | Long Descr | Chimerism (engraftment) analysis, post transplantation specimen (eg, hematopoietic stem cell), includes comparison to previously performed baseline analyses; without cell selection | 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 | Service Paid under Fee Schedule or Payment System other than OPPS | Type of Service (TOS) | 5 - Diagnostic Laboratory | Berenson-Eggers TOS (BETOS) | T1H - Lab tests - other (non-Medicare fee schedule) | MUE | 1 | CCS Clinical Classification | 234 - Pathology |
| 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 | 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. | 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. | GC | This service has been performed in part by a resident under the direction of a teaching physician | XE | Separate encounter, a service that is distinct because it occurred during a separate encounter | XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service |
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| 2012-01-01 | Added | Added |
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