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Official Description

Mucin, synovial fluid (Ropes test)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The Ropes test, also known as the mucin clot test, is a diagnostic procedure performed on synovial fluid, which is the lubricating fluid found in joints. This test is specifically designed to assess the integrity of hyaluronic polymers within the synovial fluid, which can be indicative of inflammatory damage. During the procedure, synovial fluid is aspirated from the affected joint or joints, typically through a separate reportable procedure. A few drops of this fluid are then mixed with acetic acid. The response of the fluid to the acetic acid provides valuable information regarding the presence and extent of inflammation. In cases where there is no inflammation or only mild inflammation, such as in osteoarthritis, trauma, or hemophilic arthritis, the fluid will form a solid clot. Conversely, in the presence of inflammatory conditions like subacute or chronic systemic lupus erythematosus (SLE) and rheumatoid arthritis, the test will yield a soft clot accompanied by a slightly turbid solution. In more severe cases, such as septic arthritis or acute crystalline (gouty) arthritis, the solution will appear turbid with either a crumbling clot or no clot at all, indicating significant inflammatory processes at work. This test is crucial for differentiating between various types of joint conditions and guiding further management and treatment options.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The Ropes test is indicated for the evaluation of synovial fluid in various clinical scenarios where joint inflammation is suspected. The following conditions may warrant the performance of this test:

  • Osteoarthritis This degenerative joint disease is characterized by the breakdown of cartilage and can lead to mild inflammation, which the Ropes test can help assess.
  • Trauma Joint injuries may result in the accumulation of synovial fluid, and the Ropes test can help determine the inflammatory status of the fluid.
  • Hemophilic Arthritis This condition, resulting from bleeding disorders, can lead to joint inflammation, making the Ropes test relevant for evaluation.
  • Systemic Lupus Erythematosus (SLE) In cases of subacute or chronic SLE, the test can help identify the presence of inflammatory changes in the synovial fluid.
  • Rheumatoid Arthritis This autoimmune condition often leads to significant joint inflammation, which can be assessed through the Ropes test.
  • Septic Arthritis The presence of infection in the joint can be evaluated using this test, particularly when the fluid shows turbid characteristics.
  • Acute Crystalline Arthritis (Gout) The Ropes test can assist in identifying inflammatory responses associated with gout, characterized by the presence of urate crystals.

2. Procedure

The Ropes test involves several key procedural steps to ensure accurate assessment of the synovial fluid. First, the clinician performs a joint aspiration, which is a separate reportable procedure, to obtain synovial fluid from the affected joint or joints. This is typically done using a sterile needle and syringe to minimize the risk of infection and ensure the integrity of the sample. Once the fluid is collected, a few drops are carefully dispensed into a test tube containing acetic acid. The acetic acid serves to precipitate the mucin present in the synovial fluid. After mixing, the clinician observes the reaction of the fluid. If the fluid forms a solid clot, this indicates that there is no inflammation or only mild inflammation present. In contrast, if a soft clot is formed along with a slightly turbid solution, this suggests the presence of inflammatory conditions such as subacute or chronic SLE or rheumatoid arthritis. In cases of septic arthritis or acute crystalline arthritis, the fluid will appear turbid with either a crumbling clot or no clot at all, indicating significant inflammatory activity. This step-by-step evaluation allows for the differentiation of various joint conditions based on the characteristics of the synovial fluid.

3. Post-Procedure

After the Ropes test is completed, the clinician may provide specific post-procedure care instructions to the patient. It is important to monitor the patient for any signs of complications, such as infection at the aspiration site. Patients may be advised to rest the affected joint and apply ice to reduce any potential swelling or discomfort. The results of the Ropes test will typically be reviewed in conjunction with the patient's clinical history and other diagnostic findings to formulate an appropriate treatment plan. Follow-up appointments may be scheduled to discuss the results and any necessary interventions based on the findings of the test.

Short Descr ASSAY SYNOVIAL FLUID MUCIN
Medium Descr MUCIN SYNOVIAL FLUID ROPES TEST
Long Descr Mucin, synovial fluid (Ropes test)
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 2
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.
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.
96 Habilitative services: when a service or procedure that may be either habilitative or rehabilitative in nature is provided for habilitative purposes, the physician or other qualified health care professional may add modifier 96 to the service or procedure code to indicate that the service or procedure provided was a habilitative service. habilitative services help an individual learn skills and functioning for daily living that the individual has not yet developed, and then keep and/or improve those learned skills. habilitative services also help an individual keep, learn, or improve skills and functioning for daily living.
GW Service not related to the hospice patient's terminal condition
LT Left side (used to identify procedures performed on the left side of the body)
RT Right side (used to identify procedures performed on the right side of the body)
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Pre-1990 Added Code added.
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