Continuous or Intermittent Monitoring of Glucose in the Interstitial Fluid
Tight glucose control in patients with diabetes has been associated with improved outcomes. Several devices are available to measure glucose levels automatically and frequently (e.g., every 5 to 10 minutes). The devices measure glucose in the interstitial fluid and are approved as adjuncts to traditional self-monitoring of blood glucose levels.
The advent of blood glucose monitors for use by patients in the home over 20 years ago revolutionized the management of diabetes. Using fingersticks, patients could monitor their blood glucose level both to determine the adequacy of hyperglycemia control and to evaluate hypoglycemic episodes. Tight diabetic control, defined as a strategy involving frequent glucose checks and a target hemoglobin A1c (HgA1c) in the range of 7%, is now considered standard of care for diabetic patients. Randomized controlled trials (RCTs) of tight control have demonstrated benefits for type I diabetics in decreasing microvascular complications. The impact of tight control on type II diabetic patients and on macrovascular complications such as stroke or myocardial infarction is less certain.
However, tight glucose control requires multiple measurements of blood glucose each day (i.e., before meals and at bedtime), a commitment that some patients may be unwilling or unable to meet. In addition, the goal of tight glucose control has to be balanced with an associated risk of hypoglycemcia. An additional limitation of periodic self-measurements of blood glucose is that glucose values are seen in isolation and trends in glucose levels are undetected. For example, while a diabetic's fasting blood glucose level might be within normal values, there might be undetected hyperglycemia postprandially, leading to elevated hemoglobin A1C values.
Recently, measurements of glucose in interstitial fluid have been developed as a technique of automatically measuring glucose values throughout the day, producing data that show the trends in glucose measurements, in contrast to the isolated glucose measurements of the traditional blood glucose measurements. Although devices measure glucose in interstitial fluid on a periodic rather than a continuous basis, this type types of monitoring is referred to as continuous glucose monitoring (CGM).
Several devices have received U.S. Food and Drug Administration (FDA) approval. The first two approved devices were the Continuous Glucose Monitoring System (CGMS®) (MiniMed), which uses an implanted temporary sensor in the subcutaneous tissues, and the GlucoWatch G2® Biographer, an external device worn like a wristwatch that measures glucose in interstitial fluid extracted through the skin with an electric current (referred to as reverse iontophoresis).
Additional devices that have subsequently been approved include those for pediatric use and those with more advanced software, more frequent measurements of glucose levels, more sophisticated alarm systems, etc. Devices initially measured interstitial glucose every 5 to 10 minutes and, with currently available devices the time intervals at which interstitial glucose is measured ranges from every 1-2 minutes to 5 minutes. While continuous glucose monitors potentially eliminate or decrease the number of required daily fingersticks, it should be noted that, according to the FDA labeling, monitors are not intended to be an alternative to traditional self-monitoring of blood glucose levels but rather provide adjunct monitoring, supplying additional information on glucose trends that are not available from self-monitoring. In addition, it is important to note that devices may be used intermittently, e.g., time periods of 72 hours, or on a long-term basis.
In addition to stand-alone continuous glucose monitors, several insulin pump systems have included a built-in CGM. This policy addresses continuous glucose monitoring devices, not the insulin pump portion of these systems.
Several continuous glucose monitoring systems have been approved by the FDA through the premarket approval process:
Related medical policies -
Intermittent monitoring, i.e., up to 72 hours, of glucose levels in interstitial fluid may be considered medically necessary in patients with type I diabetes mellitus whose diabetes is poorly controlled, despite current use of best practices (see Policy Guidelines). Poorly controlled type I diabetes mellitus includes the following clinical situations: unexplained hypoglycemic episodes, hypoglycemic unawareness, suspected postprandial hyperglycemia, and recurrent diabetic ketoacidosis.
Intermittent monitoring of glucose levels in interstitial fluid may also be considered medically necessary in patients with type I diabetes prior to insulin pump initiation to determine basal insulin levels.
Continuous, i.e., long-term, monitoring of glucose levels in interstitial fluid, including real-time monitoring, as a technique of diabetic monitoring, may be considered medically necessary when the following situations occur, despite use of best practices:
Other uses of continuous monitoring of glucose levels in interstitial fluid as a technique of diabetic monitoring are considered investigational.
Federal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.
Several insulin pump systems (e.g., Omnipod Insulin Management System, Paradigm® REAL-Time System) have a built-in continuous glucose monitor (CGM). This policy is evaluating the CGM-device only; the policy does not evaluate insulin pumps. Insulin pumps are addressed in the External Infusion Pumps policy.
Best practices in diabetes control for patients with diabetes mellitus include compliance with a regimen of 4 or more fingersticks each day and use of an insulin pump. During pregnancy, 3 or more insulin injections daily could also be considered best practice for patients not on an insulin pump prior to the pregnancy. Prior use of an intermittent (72-hour) glucose monitor would be considered a part of best practices for those considering use of a continuous glucose monitor.
Women with type I diabetes mellitus taking insulin who are pregnant or about to become pregnant with poorly controlled diabetes are another subset of patients to whom the policy statement on intermittent monitoring may apply.
Intermittent monitoring is generally conducted in 72-hour periods. It may be repeated at a subsequent time depending on the patient's level of diabetes control.
The strongest evidence exists for use of CGM devices in patients age 25 and older. However, age may be a proxy for motivation and good control of disease, so it is also reasonable to select patients based on their ability to self-manage their disease, rather than age.
Investigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
2/2001: Approved by Medical Policy Advisory Committee (MPAC)
4/2/2001: CPT code 84945 and ICD-9 procedure code 99.99 deleted. ICD-9 diagnosis code 250.23 and 250.33 added.
2/15/2002: Investigational definition added
2/25/2002: Code Reference, Sources and Place of Service sections updated
3/13/2002: E0609 deleted, 92950 (typo) should have been 95250, 99091 moved to non-covered
4/18/2002: Type of Service and Place of Service deleted
4/17/2003: FDA approved labeling for the GlucoWatch "first bullet" expanded to include children/adolescents (age 7 to 17)
6/12/2003: Clarification of changes 4/17/2003. GlucoWatch® G2™ Biographer (G2™ Biographer) information added to Description section.
9/5/2003: Policy reviewed, no changes
10/16/2003: GlucoWatch clarification statement added to "Policy" section
1/27/2004: Sources updated
2/10/2004: Sources updated
11/3/2004: Code Reference section reviewed, no changes
3/13/2006: Coding updated. CPT4 2006 revisons added to policy
3/20/2006: Policy reviewed, no changes
3/27/2007: Policy reviewed and updated. Covered codes table deleted. CPT codes 95250, 95251, and HCPCS S1031 moved to non-covered. Removed the following policy statement, "Continuous monitoring of glucose in the interstitial fluid is considered investigational except for patients with type 1 diabetes who have not achieved adequate glycemic control in spite of frequent self-monitoring of fingerstick blood glucose levels. BCBSMS will only approve the MiniMed monitoring system. Usage of which will be for a finite period of time (Rental)."
7/19/2007: Reviewed and approved by MPAC
12/17/2007: Coding updated. CPT/HCPCS 2008 revisions added to policy.
4/25/2008: Policy reviewed, description section updated
12/31/2008: Code reference section updated per the 2009 CPT/HCPCS revisions
1/8/2009: Policy reviewed and updated. Policy statement updated to allow intermittent monitoring in patients with type I diabetes whose diabetes is poorly controlled, prior to insulin pump initiation to determine basal insulin levels and according to best practice guidelines. Policy guidelines updated to include Best Practice guidelines.Codes updated to reflect covered codes.
04/26/2010: Added “or Intermittent” to the policy title. Policy description and statement unchanged. FEP verbiage added to the Policy Exceptions section. Deleted outdated references from the Sources section.
04/20/2011: Policy reviewed; no changes.
04/26/2012: Policy reviewed; policy statement unchanged. Policy guidelines updated to state the following: Several insulin pump systems (e.g., Omnipod Insulin Management System, Paradigm REAL-Time System) have a built-in continuous glucose monitor (CGM). This policy is evaluating the CGM-device only; the policy does not evaluate insulin pumps. Insulin pumps are addressed in the External Infusion Pumps policy.
09/03/2013: Added the following investigational policy statement: Use of an artificial pancreas system, including but not limited to closed-loop monitoring devices with low-glucose suspend (LGS) features, are considered investigational. Deleted "symptomatic" from the first bullet in the third policy statement. Intent of policy statement unchanged.
04/23/2014: Policy reviewed; description updated regarding available devices. Added "mellitus" to the first policy statement. Intent of policy statement unchanged.
08/26/2015: Policy description updated to remove information regarding artificial pancreas device systems. Removed the following policy statement: Use of an artificial pancreas system, including but not limited to closed-loop monitoring devices with low-glucose suspend (LGS) features, are considered investigational. Policy guidelines updated. Medical policy revised to add ICD-10 codes.
Blue Cross Blue Shield Association Policy # 1.01.20
This may not be a comprehensive list of procedure codes applicable to this policy.
The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.