(Reproduced by permission from Medicare Focus, May 2000, Web Edition)

Medicare Part A Local Medical Review Policy
Therapeutic Drug Assay - Digoxin

Policy Number:

A97-12 – Revision

Description

Determination of drug levels is important when the potential for drug toxicity is significant, or when inadequate or undesirable response follows the use of a standard dose. It provides an easier and more rapid estimation of dosage requirements than does observation of the drug's effects themselves.

Type of Bill

12X, 13X, 14X, 22X, 23X, 24X, 28X, 71X, 72X, 73X, 83X, 85X

Revenue Codes

30X

Indications and Limitations of Coverage and/or Medical Necessity

Indications

Digoxin assay is indicated for the following reasons:

·	Subtherapeutic response (either a, b, c, or d)
	a.	No improvement or worsening of congestive heart failure or atrial fibrillation or flutter
	b.	Suspected noncompliance
	c.	Concomitant use of an interacting drug (antacids, a kaolin and pectic combination [Kaopectate], neomycin, quinidine, spironolactone, nifedipine, cholestyramine, verapamil)
	d.	Suspected malabsorption
·	Suspected toxicity (either a or b)
	a.	Appearance of arrhythmias suspected to be caused by digoxin (supraventricular tachycardia, atrioventricular conduction defects, multifocal premature ventricular contractions)
	b.	Noncardiac signs or symptoms of digoxin toxicity (visual changes, anoremia, nausea, vomiting, diarrhea, abdominal pain, confusion, headache)
·		High-risk patient (unstable or declining renal function, low serum potassium level, hypoxia, recent increase in diuretic dose)
·		Initiation of digoxin therapy or dosage adjustment after steady state reached.

Limitations

It requires four to five half-lives (one half-life is approximately 30 hours) for the drug to reach a new steady state after any change in the digoxin dosage. Thus, after a change in dosage, digoxin concentrations should not be checked for at least several days (unless there are signs or symptoms of toxicity) since the serum digoxin will not be at steady state.

The use of digoxin assay in the diagnosis of drug toxicity is based on the observation that in patients with clinical manifestations of digitalis toxicity generally the serum digoxin assay is in excess of 2ng/ml. Because of the wide overlap of individual readings, serum levels above 2 ng/ml are not necessarily indicative of digitalis toxicity. Thus, the predictive value of the assay in an individual patient is small. No study has established the utility of prospective measurement of digoxin levels to assist in either the diagnosis or prevention of digoxin toxicity.

Thus, routine monitoring of serum digoxin levels is unlikely to provide any clinically relevant information. Therefore, measurements of digoxin levels should be confined to situations where the clinician has a specific need for the information as outlined under "Indications."

Allowing for initiation of therapy, concurrent illness, or dosage changes in any one patient, it is generally not considered medically necessary to perform a therapeutic drug assay for digoxin more often than four times per year.

Screening tests are defined as those tests done in the course of an annual physical examination or as part of a routine physical checkup, without signs, symptoms or the presence of an illness. The test covered by this local medical review policy when done as a screening test would not be a covered Medicare benefit.

CPT/HCPCS Codes

80162

Digoxin

ICD-9-CM Codes That Support Medical Necessity

One of the following covered ICD-9-CM diagnosis code(s) must be linked to the appropriate procedure.

The correct use of an ICD-CM code listed below does not guarantee coverage of a service. The service must be reasonable and necessary in the specific case and must meet the criteria specified in this policy.

Diagnosis Definition

The following list is not intended to be all inclusive, but only to provide examples of diagnoses and clinical situations for which coverage may be provided:

Hypertensive Disease
402.00 - 402.01
402.10 - 402.11
402.90 - 402.91
404.01
404.03
404.11
404.13
Other Forms of Heart Disease
425.0
425.2 - 425.5
425.9
427.0 - 427.2
427.31 - 427.32
427.41 - 427.42
427.60 - 427.61
427.69
427.81
427.89
428.0 - 428.1
428.9
429.0 - 429.6
429.71
429.81 - 429.82
429.89
429.9
Poisoning by Drugs, Medicinal and Biological Substances
972.1
Persons Encountering Health Services for Specific Procedures and Aftercare
V58.69
V58.83 Revised per Medicare Focus June, 2001

HCPCS Section and Benefit Category

Pathology and Laboratory

HCFA National Coverage Policy

Title XVIII of the Social Security Act, Section 1862(a)(1)(A). This section allows coverage and payment for only those services that are considered to be reasonable and medically necessary, i.e., reasonable and necessary are those tests used in the diagnosis and management of illness or injury or to improve the function of a malformed body part.

Title XVIII of the Social Security Act, Section 1862(a)(7). This section excludes routine physical examinations.

Reasons for Denial

This test is not indicated on a routine basis when the patient exhibits no symptoms of too low or too high dosage.

Services will always be denied which are considered:

·	experimental; or
·	cosmetic; or
·	routine screening; or
·	a program exclusion; or
·	never medically necessary; or
·	otherwise not covered.

Non-covered ICD-9-CM Diagnosis Codes

Any code not listed in the "ICD-9-CM Codes That Support Medical Necessity" section of this policy.

Codes that are never covered:

V70.0-V70.9
V82.9

Sources of Information

·	Laboratory Test Handbook - 3rd Edition Jacobs et al; Lexi-Comp Inc., 1994
·	Other Carriers' policies
·	Henry, JB, MD. Clinical Diagnosis and Management by Laboratory Methods, 19th Edition, W.B. Saunders Company 1996
·	Canas F, Tanasijevic MJ, Ma'luf N, Bates DW. Evaluating the Appropriateness of Digoxin Level Monitoring. Arch Intern Med 1999;Feb 22;159(4):363-8
·	Matzuk MM, Shlomchik M, Shaw LM. Making Digoxin Therapeutic Drug Monitoring More Effective. Ther Drug Monit 1991;May13(3):215-9
·	Brass, EP. Drug Concentrations. A Guide to Their Usefulness in Clinical Practice. Postgrad Med 1987;Jul;82(1):83-7,90.
·	Selzer A. Role of Serum Digoxin Assay in Patient Management. J Am Coll Cardiol 1985;May;5(5 Suppl A):106A-110A.

Coding Guidelines

This test is properly billed with the ICD-9-CM code of the disease process requiring digoxin administration.

Report the principal diagnosis (Form Locator 67) to your highest degree of certainty. Secondary diagnosis codes (Form Locator 68-75) should include the patient's presenting symptoms and any other medical conditions that may affect the patient’s care (Refer to the May 1999 issue of Medicare Focus).

Reconsiderations and Appeals - Claims resubmitted with a different diagnosis code must include medical record documentation to justify the diagnosis code change. Submission with diagnoses other than those listed in the "ICD-9-CM Codes That Support Medical Necessity" section of this policy, will be individually reviewed by this Intermediary for medical necessity.

Documentation Requirements

Documentation supporting the medical necessity of this item, such as ICD-9-CM codes, must be submitted with each claim. Claims submitted without such evidence will be denied as being not medically necessary.

All coverage criteria must be documented in the patient’s medical record and made available to Medicare upon request. Medical record documentation of symptoms, other abnormal laboratory values, other prescribed drugs, and a notation of the test result and its implications is expected. This information should be generally submitted on reconsideration only (or with the claim if the services are unusual or if denial is anticipated).

ICD-9-CM diagnosis codes are required on claim.

If documentation is requested for review, submit the following:

·	History and Physical
·	Physician orders/progress notes
·	Nurses notes
·	Medication sheet indicating the name of drug, the dosage and route administered
·	Diagnosis/reason for drug
·	Test results
·	Itemization of charges

Comments

This Local Medical Review Policy replaces any other previously published policy and/or items related to therapeutic drug assay-digoxin.

This policy should be interpreted to incorporate future changes in the ICD-9-CM or CPT/HCPCS coding systems such that its original intent and scope will not be substantively changed.

CPT only ^© 1999 American Medical Association. All Rights Reserved.

All International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes and descriptions are copyright ^© 1998 Medicode, Inc.

	Original	Revised
Start Date of Comment Period	June 1996	January 25, 2000
Start Date of Notice Period	October, 1996	May 1, 2000
Original Effective Date	November 1, 1996
Revised Effective Date	August. 1, 1997		June 1, 2000
Revision History	Revised and republished June 1, 1998

Approval

This policy does not reflect the sole opinion of the Intermediary/Medical Director. Although the final decision rests with the Intermediary, this policy was developed in conjunction with the other Intermediaries and other Intermediary policies.