Test ID: MBL
Mannose-Binding Lectin, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Evaluation of children and adults with a clinical history of recurrent infections
Results may be useful for genetic counseling and support aggressive management of recurrent infections in patients with reduced levels of mannose-binding lectin
Method Name A short description of the method used to perform the test
Enzyme-Linked Immunosorbent Assay (ELISA)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Forms: If not ordering electronically, submit a General Request Form (Supply T239) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild reject; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | Mild OK; Gross OK |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen | 7 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Mannose-binding lectin (MBL) is a member of the collectin family of proteins that are characterized structurally by the presence of collagenous regions and lectin domains in the same subunit. The subunit structure of MBL is comprised of three 32kDa peptide chains organized in a triple helix with 3 C-terminal lectin domains. Circulating (functional) MBL is comprised of oligomers of subunits (dimers through tetramers account for approximately 75% of circulating MBL) that are associated with an MBL-associated serine protease (MASP). There is a single MBL gene (4 exons) on chromosome 10 with 4 known allelic variants: wild type MBL (A), and 3 mutant forms B, C, and D caused by point mutations in 3 different codons. The mutant forms of MBL form oligomers poorly, and have diminished complement activating activity (see below). Multimeric MBL binds to many different oligosaccharide moieties, including those in the cell walls of many different bacteria, yeasts, and some viruses, including HIV 1, HIV 2, and influenza A. Binding of MBL results in complement activation by the classical pathway through activation of complement 4 (C4) by MASP, and surface bound MBL enhances phagocytosis by interacting with collectin receptors on phagocytic cells. Mutations of MBL codons (homozygous or heterozygous haplotypes) are associated with diminished opsonophagocytic activity and diminished serum levels of MBL measured immunochemically (MBL deficiency). MBL-deficient individuals have increased susceptibility to infection particularly if MBL deficiency occurs concomittantly with another heritable immune system abnormality, eg, C4 null alleles or immunoglobulin class or subclass deficiencies.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
> or =7.8 ng/mL
This reference range applies only to adults.
See Cautions for further information regarding the reference range and clinical interpretation.
Interpretation Provides information to assist in interpretation of the test results
Diminished levels of serum mannose-binding lectin (MBL) are consistent with the diagnosis of MBL deficiency.
Levels <7.8 ng/mL are associated with homozygous or mixed heterozygous mutant forms of MBL or mutations in the MBL promoter gene.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Measurement of mannose-binding lectin (MBL) immunochemically is highly dependent on the specificity of reagent anti-MBL antibody used to bind and detect MBL. Antibodies that detect multimers correlate with functional MBL activity and can be used to screen suspected individuals for functional MBL deficiency. Measured with multimer specific anti-MBL, the frequency distribution of MBL levels in sera from healthy individuals is multimodal. According to a reference range study conducted at Mayo Clinic, approximately 14% of healthy individuals may have a measurable level <100 ng/mL. Accordingly, levels <100 ng/mL should be interpreted in the clinical context of the patient. The finding of a markedly reduced level of MBL may also occur in some healthy individuals. Identification of MBL deficiency does not exclude other etiologies that predispose to increased risk of infection.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Pettigrew HD, Teuber SS, Gershwin ME: Clinical significance of complement deficiencies. Ann NY Acad Sci 2009;1173:108-123
2. Botto M, Kirschfind M, Maco P, et al: Complement in human diseases: lessons from complement deficiencies. Mol Immunol 2009;48:2774-2783
3. Thiel S, Frederiksen PD, Jensenius JC: Clinical manifestations of mannan-binding lectin deficiency. Mol Immunol 2006;43:86-96
Method Description Describes how the test is performed and provides a method-specific reference
Oligomers of mannose-binding lectin (MBL) (functional MBL) are measured by enzyme immunosorbent assay (ELISA) in microtiter plates adsorbed with HYB 131-01 mouse monoclonal antibody. This antibody binds structurally normal MBL from A/A genotype donors, but detects little or no structurally abnormal MBL from other haplotypes. Monoclonal anti-MBL is used both as a capture antibody and as a detection protein in this microtiter immunoassay. The assay is conducted by incubating diluted serum in the microtiter plate, followed by washing and a second incubation with biotin-labeled antibody. After a second wash step, the plate is incubated with streptavidin-horseradish peroxidase (HRP) followed by 3,3',5,5' tetramethylbenzidine (TMB) substrate. Absorbance is read at 450 nm and the results compared to an 8-point standard curve (0, 0.5, 1.0, 2.0, 5.0, 10.0, 20.0, and 40.0 ng/mL).(Package insert: MBL-Oligomer ELISA Kit, BioPorto Diagnostics, Gentofte, Denmark)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Tuesday; 9 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83520
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| MANBL | Mannose-Binding Lectin, S | 30152-3 |
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