CPT® Code 89049

Official Description

Caffeine halothane contracture test (CHCT) for malignant hyperthermia susceptibility, including interpretation and report

Common Language Description

The Caffeine Halothane Contracture Test (CHCT) is a specialized laboratory procedure designed to assess an individual's susceptibility to malignant hyperthermia (MH). Malignant hyperthermia is a rare but potentially fatal condition that can be triggered by certain anesthetic agents, particularly volatile anesthetics and neuromuscular blocking agents used during general anesthesia. The underlying mechanism of MH involves a rapid and uncontrolled increase in oxidative metabolism within striated skeletal muscle, which is primarily due to abnormal calcium handling within muscle cells. This condition can lead to severe physiological disturbances, including muscle rigidity, elevated body temperature, tachycardia, increased carbon dioxide production, decreased oxygen levels, and acidosis, all resulting from hyper-metabolic activity in the muscle tissue. Symptoms of MH may manifest as rigidity of the masseter muscle or generalized muscle stiffness, alongside other critical signs such as elevated body temperature and altered blood gas levels. Additionally, the breakdown of muscle tissue, known as rhabdomyolysis, can occur, leading to the release of myoglobin into the bloodstream, which poses a risk of acute kidney injury and cardiac complications. Individuals at risk for malignant hyperthermia may have a family history of the condition, previous unexplained fevers, episodes of rhabdomyolysis, or symptoms such as dark-colored urine or heat stroke. The CHCT involves obtaining a sample of striated muscle tissue through a biopsy, which is a separately reportable procedure. The fresh muscle fibers are then subjected to electrical stimulation in a controlled environment, and their contraction responses are measured. Following this, the muscle fibers are exposed to ryanodine receptor agonists, specifically caffeine and halothane, to evaluate their contractile response. A significant increase in muscle contraction force in response to these agents indicates a high likelihood of malignant hyperthermia susceptibility. The CPT® Code 89049 encompasses the entire process, including the pathologist's review of patient records, the interpretation of test results, and the generation of a comprehensive written report detailing the findings.

1. Indications

The Caffeine Halothane Contracture Test (CHCT) is indicated for individuals who may be at risk for malignant hyperthermia (MH). The following conditions and factors warrant the performance of this test:

Family History of MH: A documented family history of malignant hyperthermia increases the likelihood of susceptibility in the individual being tested.
Unexplained Fevers: A history of unexplained fevers that have been evaluated to exclude other diagnoses may suggest a predisposition to MH.
Previous Rhabdomyolysis: Episodes of rhabdomyolysis that have been investigated to rule out other causes can indicate a potential risk for MH.
Symptoms of Dark-Colored Urine: A history of dark-colored urine, which may be associated with muscle breakdown, can be a sign of underlying muscle pathology related to MH.
Heat Stroke History: Previous experiences of heat stroke may also contribute to the assessment of MH susceptibility.

2. Procedure

The Caffeine Halothane Contracture Test (CHCT) involves several critical procedural steps to accurately assess malignant hyperthermia susceptibility:

Step 1: Muscle Biopsy: A sample of striated muscle tissue is obtained through a biopsy procedure. This step is essential as it provides the necessary muscle fibers for testing. The biopsy is performed in a controlled clinical setting, ensuring that the tissue is collected safely and effectively.
Step 2: Preparation of Muscle Fibers: Once the muscle tissue is obtained, fresh muscle fibers are carefully prepared and placed into a contraction chamber. This chamber allows for controlled electrical stimulation of the muscle fibers, which is crucial for measuring their contractile responses.
Step 3: Electrical Stimulation: The muscle fibers are subjected to electrical stimulation to record their initial contraction response. This baseline measurement is important for comparison with subsequent tests involving ryanodine receptor agonists.
Step 4: Exposure to Ryanodine Receptor Agonists: The muscle fibers are then exposed to ryanodine receptor agonists, specifically caffeine and halothane. These agents are known to provoke a contractile response in susceptible muscle fibers. The contraction response is measured again to assess the degree of muscle contraction.
Step 5: Interpretation of Results: A significant increase in muscle contractile force in response to caffeine and halothane indicates a high likelihood of malignant hyperthermia susceptibility. The results are then compiled for further analysis.

3. Post-Procedure

After the completion of the Caffeine Halothane Contracture Test, the patient may be monitored for any immediate post-procedural effects related to the biopsy. Recovery from the biopsy itself is typically straightforward, but patients should be advised to report any unusual symptoms. The pathologist will review the test results, interpret the findings, and generate a comprehensive written report detailing the susceptibility to malignant hyperthermia. This report is crucial for informing future anesthetic management and ensuring patient safety during surgical procedures.

Short Descr	CHCT FOR MAL HYPERTHERMIA
Medium Descr	CAFFEINE HALOTHANE CONTRACTURE TEST
Long Descr	Caffeine halothane contracture test (CHCT) for malignant hyperthermia susceptibility, including interpretation and report
Status Code	Active Code
Global Days	XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC)	0 - Physician Service Code
Multiple Procedures (51)	0 - No payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50)	0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions	09 - Concept does not apply.
Assistant Surgeon (80, 82)	0 - Payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62)	0 - Co-surgeons not permitted for this procedure.
Team Surgery (66)	0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family	99 - Concept Does Not Apply
APC Status Indicator	STV-Packaged Codes
Type of Service (TOS)	5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS)	T1G - Lab tests - other (Medicare fee schedule)
MUE	1
CCS Clinical Classification	235 - Other Laboratory