Serologic Diagnosis of Celiac Disease

POLICY NUMBER

L.2.04.425

DESCRIPTION

Celiac disease, which may also be referred to as celiac sprue or gluten-sensitive enteropathy, may be defined as small intestinal inflammation resulting from an immunologic intolerance to gluten; i.e. the proteins derived from wheat, barley and rye. The diagnosis is confirmed when there is a clinical and histologic improvement on a strict gluten free diet, and relapse when dietary gluten is reintroduced. As summarized in the following table, the symptoms of the disease are markedly variable and can be broadly subdivided into intestinal and extraintestinal manifestations, the latter thought to be related to nutrient malabsorption. For example, osteopenia and osteoporosis, commonly seen in adults with untreated celiac disease, is related to the impaired absorption of vitamin D and binding of intraluminal calcium and magnesium to unabsorbed dietary fatty acids, forming insoluble soaps.

Clinical Manifestation of Celiac Disease

As noted above, the symptoms of celiac disease are nonspecific and are often overlooked. In addition, the disease may develop at any time in life from infancy to very old age. In children, the disease typically presents between 6 and 24 months, following weaning, and is characterized by abnormal stools, poor appetite and irritability. In adults, diarrhea is the main presenting symptom, but presenting symptoms may be entirely nonspecific, such as anemia or infertility. "Typical" or "classical" celiac disease refers to the presence of malabsorption, while "atypical" celiac disease consists primarily of extraintestinal manifestations. Finally, silent celiac disease may be entirely asymptomatic and discovered only on biopsy or with serologic testing (see further discussion below). For example, population-based screening serologic surveys suggest a prevalence of 1 in 250-500 in most countries, including the United States. Celiac disease is an HLA-associated disease and therefore there is a hereditary component to the disease, with a 10% prevalence among first degree relatives. Celiac disease is associated with a number of other conditions, including type 1 diabetes mellitus, rheumatoid arthritis and primary biliary cirrhosis.

Given the nonspecific nature of the symptoms, definitive diagnosis has been based on the results of small intestinal biopsies showing a flattened intestinal mucosa in association with an inflammatory infiltrate. Diagnostic criteria were first established in 1969 by the European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHN) and consisted of a series of three intestinal biopsies, one at diagnosis, one after institution of a gluten free diet, and the third after a repeat gluten challenge. This cumbersome method of diagnosis was revised in 1990 by simplifying the diagnostic criteria to a positive biopsy at presentation in conjunction with consistent history and serologic results, followed by a clinical response to a gluten free diet.

While a positive biopsy is still considered the gold standard for diagnosis, there has been considerable interest in the serologic evaluation of patients with possible celiac disease, in part as a technique to triage the large number of patients with nonspecific symptoms for biopsy. Serologic diagnosis is focused on the detection of IgA antibodies. In the presence of gluten, the intestine produces large amounts of antibodies that are secreted intraluminally, but spill over into the serum, where they can be detected. Antigliadin antiendomysial, and tissue transglutaminase IgA antibodies have been most extensively studied. Gliadin is a component of gluten, while antiendomysial antibodies (referred to as EMA) are directed against the reticulin network surrounding the smooth muscle bundles of the gastrointestinal tract. Tissue transglutaminase is the enzyme responsible for deamidation of gliadin in the lamina propria, increasing its immunogenicity and allowing interaction with HLA-DQ2 or HLA-DQ8.

Antigliadin antibodies can be detected using an ELISA test. EMA antibodies are detected using an indirect immunofluorescence technique using either primate esophagus or human umbilical cord as a substrate. More recently the EMA antigen has been identified as the tissue enzyme tissue transglutaminase (tTG), allowing the development of an ELISA based test or a dot blot procedure that can be performed in the physician's office. A total of 2-3% of patients with celiac disease are IgA deficient; in these patients IgG antibodies are assayed instead of IgA antibodies. Among the approximately 10% of cases where clinical suspicion, serologic testing  and intestinal biopsy are equivocal, the 2007 review by Green and Cellier suggests that negative tests for HLA-DQ2 and HLA-DQ8 (present in 90-95% and 5+% of patients with celiac disease respectively) can rule out a diagnosis of celiac disease.

The newest serologic tests are deamidated gliadin peptide (DGP) antibody tests. Deamidation refers to a chemical reaction in which an amide group is removed from an organic compound. Deamidated gliadin is produced when gluten undergoes acid or enzymatic treatment so that tissue transglutaminase converts some of the glutamines to glutamic acid. Deamidated peptides are believed to be more specific to celiac disease than native peptides. A limitation of human antigen-based tTG tests for diagnosing celiac disease is that they have relatively low specificity and can result in false-positive findings in patients with chronic liver disease, inflammatory bowel disease, diabetes and other conditions. Some of the DGP antibody tests are able to assay both IgA and IgG, so they can be used in patients regardless of IgA deficiency status.

Antibody testing for celiac disease is widely available and HLA typing for celiac disease is offered by several laboratories such as Quest, LabCorp and Promethus. 

POLICY

Serologic measurement of tissue transglutaminase or antiendomysial antibodies may be considered medically necessary in patients with signs or symptoms suggestive of celiac disease when more common pathogens have been previously ruled out. Testing is limited to once per lifetime.

Serologic measurement of antigliadin antibodies may be considered medically necessary in children under 24 months of age with signs or symptoms suggestive of celiac disease when more common pathogens have been previously ruled out. Testing is limited to once per lifetime.

Serological testing is considered medically necessary to screen persons with type 1 diabetes mellitus for celiac disease.

Serologic measurement of deamidated gliadin peptide antibodies is considered investigational in patients with signs or symptoms suggestive of celiac disease.

HLA-DQ2 and HLA-DQ8 testing may be considered medically necessary to rule out celiac disease in patients with discordant serologic and histologic (biopsy) findings or if persistent symptoms warrant testing despite negative serology and histology.

Screening of asymptomatic at risk patient groups for celiac disease using one or more serologic IgA or IgG measures is considered investigational.

Population screening for celiac disease using one or more serologic IgA or IgG measures is considered investigational.

POLICY EXCEPTIONS

None

POLICY GUIDELINES

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Mental Health Disorders, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:

A.  consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and

B.  appropriate with regard to standards of good medical practice; and

C.  not solely for the convenience of the Member, his or her Provider; and

D.  the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.

For the definition of medical necessity, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.

Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.

POLICY HISTORY

7/2003: Approved by Medical Policy Advisory Committee (MPAC)

10/19/2006: Policy updated to allow testing as medically necessary

5/29/2008: Policy statement updated with the following as medically necessary: addition of tissue transglutaminase, the use of antigliadin antibodies for children under 18 months of age and HLA-DQ2 and –DQ8 testing to rule out celiac disease where serology and histology are equivocal. Additional policy statements added that screening both the general population and asymptomatic at risk subgroups are investigational.

04/19/2011: Policy description updated regarding available tests. Policy statement updated to state that serologic measurement of deamidated gliadin peptide antibodies is considered investigational in patients with signs or symptoms suggestive of celiac disease. Also, added that the use of more than one antibody test is considered not medically necessary.

04/19/2012: Deleted the following policy statement: Use of more than one antibody test is considered not medically necessary. The age limit for testing in children was changed from 18 months to 24 months.

08/20/2013: Added the following policy statement: Serological testing is considered medically necessary to screen persons with type 1 diabetes mellitus for celiac disease. Code Reference section updated to add the code range for diabetes mellitus, type I.

08/14/2015: Medical policy revised to add ICD-10 codes.

06/07/2016: Policy number L.2.04.425 added. Policy Guidelines updated to add medically necessary and investigative definitions.

12/16/2021: Code Reference section updated to add new CPT codes 86231 and 86364 as covered and CPT code 86258 as investigational, effective 01/01/2022. Added ICD-10 diagnosis codes K00.3, K00.4, K03.7, K12.0, K14.0, K59.1, K90.9, L11.0, L12.0, L12.2, L13.0, L87.0, P78.3, R14.0, R62.51, R62.52, R62.7, R63.0, and R63.4. Removed CPT code 86849.

05/01/2023: Policy reviewed. First two policy statements updated to add that the procedures are considered medically necessary when more common pathogens have been previously ruled out. Testing is limited to once per lifetime. Policy Guidelines updated to change "Nervous/Mental Conditions" to "Mental Health Disorders" and "Medically Necessary" to "medical necessity."

06/30/2023: Policy reviewed; no changes.

06/24/2024: Policy reviewed; no changes.

SOURCE(S)

Blue Cross Blue Shield Association policy # 2.04.30

CODE REFERENCE

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.

Covered Codes

Investigational Codes

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