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Official Description

Sugars (mono-, di-, and oligosaccharides); single quantitative, each specimen

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

A laboratory test designated by CPT® Code 84378 is utilized to measure the concentration of sugars, which include mono-, di-, and oligosaccharides, in various specimens such as blood, body fluids, or excrement. Sugars are categorized based on their molecular structure: monosaccharides are single carbohydrate units, examples of which include glucose, fructose, and galactose. Disaccharides consist of two monosaccharide units, with common examples being sucrose (composed of fructose and glucose), lactose (composed of glucose and galactose), and maltose (composed of two glucose units). The human body metabolizes these simple sugars through oxidation to generate energy. Oligosaccharides, on the other hand, are short chains of monosaccharides typically containing three to ten units. These compounds can attach to proteins and lipids, forming glycans, and are naturally found in plant fibers such as starch and cellulose. They play a significant role as prebiotics, promoting the growth of beneficial bacteria in the large intestine, which in turn aids in the production of short-chain fatty acids (SCFAs) and certain B vitamins. The test associated with code 84378 is particularly useful for screening carbohydrate malabsorption disorders and for detecting lysosomal storage diseases, including mannosidosis, fucosidosis, GM1 gangliosidosis, and sialic acid storage disease. This code is specifically applied for the quantitative analysis of a single sugar, such as when testing for galactose-1-phosphate in red blood cells using gas chromatography-mass spectrometry or measuring 1,5 anhydroglucitol in serum or plasma through a quantitative enzymatic method. For tests involving multiple sugar molecules, CPT® Code 84379 is utilized.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The laboratory test associated with CPT® Code 84378 is indicated for various clinical scenarios, particularly when there is a suspicion of carbohydrate malabsorption disorders or lysosomal storage diseases. The following conditions may warrant the use of this test:

  • Carbohydrate Malabsorption Disorders - Conditions where the body is unable to properly absorb carbohydrates, leading to gastrointestinal symptoms.
  • Lysosomal Storage Diseases - Genetic disorders that result in the accumulation of harmful substances in the body's cells, including conditions such as mannosidosis, fucosidosis, GM1 gangliosidosis, and sialic acid storage disease.

2. Procedure

The procedure for conducting the test under CPT® Code 84378 involves several key steps to ensure accurate measurement of sugar levels in the specimen. The following procedural steps are typically followed:

  • Specimen Collection - A sample is collected from the patient, which may include blood, body fluids, or excrement, depending on the specific sugars being tested.
  • Preparation of the Specimen - The collected specimen is prepared for analysis, which may involve centrifugation or other methods to isolate the sugars from the sample matrix.
  • Quantitative Analysis - The prepared specimen undergoes quantitative analysis using appropriate methods. For example, galactose-1-phosphate may be tested in red blood cells using gas chromatography-mass spectrometry, while 1,5 anhydroglucitol can be measured in serum or plasma through a quantitative enzymatic method.
  • Data Interpretation - The results of the quantitative analysis are interpreted by laboratory professionals, who assess the sugar levels in the specimen to determine if they fall within normal ranges or indicate potential disorders.

3. Post-Procedure

After the procedure associated with CPT® Code 84378, the laboratory will provide the results to the requesting physician or healthcare provider. It is essential for the provider to review the results in conjunction with the patient's clinical history and symptoms. Depending on the findings, further diagnostic testing or clinical evaluation may be necessary to confirm any suspected conditions. Additionally, the healthcare provider may discuss the implications of the test results with the patient and outline any required follow-up actions or treatments based on the findings.

Short Descr SUGARS SINGLE QUANT
Medium Descr SUGARS MONO DI&OLIGOS 1 QUANTITATIVE EACH SPEC
Long Descr Sugars (mono-, di-, and oligosaccharides); single quantitative, each specimen
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.
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
GA Waiver of liability statement issued as required by payer policy, individual case
GZ Item or service expected to be denied as not reasonable and necessary
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
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.
GW Service not related to the hospice patient's terminal condition
Date
Action
Notes
2011-01-01 Changed Short description changed.
2002-01-01 Changed Code description changed.
2001-01-01 Changed Code description changed.
1999-01-01 Added First appearance in code book in 1999.
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