Test ID: LCATD
Lecithin Cholesterol Acyltransferase Deficiency Profile
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
Detection of lecithin cholesterol acyltransferase deficiency
Profile Information A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TCS | Cholesterol, Total, CDC, S | Yes, (order CHOL) | Yes |
| CHLE | Cholesteryl Esters, S | Yes | Yes |
| PPL | Phospholipids, S | Yes | Yes |
| LPC | Lysophosphatidylcholine, P | Yes | Yes |
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
TCS/23543, CHLE/8324, PPL/8296: Enzymatic Colorimetric
LPC/83399: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Lecithin Cholesterol Acyltransferase Activity
Specimen Type Describes the specimen type needed for testing
Serum
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.
Plasma and serum are required.
Specimen Type: Plasma
Collection Container/Tube: Lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Fasting.
2. Label specimen as plasma.
Specimen Type: Serum
Collection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 2.5 mL
Collection Instructions:
1. Fasting-overnight (12-14 hours).
2. Patient must not consume any alcohol for 24 hours before the specimen is drawn.
3. Label specimen as serum.
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 OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | Mild OK; Gross reject |
| 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 |
|---|---|---|
| Plasma EDTA | Frozen | |
| Serum | Refrigerated (preferred) | 7 days |
| Frozen | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Lecithin cholesterol acyltransferase (LCAT), a glycoprotein with an apparent molecular weight of 67 kD, is the enzyme responsible for synthesizing the majority of cholesteryl esters in serum. It acts by transferring fatty acid from phosphatidylcholine to the 3-hydroxyl group of cholesterol. In serum, LCAT protein is bound to high-density lipoproteins (HDL) and it esterifies cholesterol primarily in this class of lipoproteins. The major structural protein of HDL, apolipoprotein AI (apo AI), is believed to be the principal activator of LCAT. There is evidence that serum LCAT also may act directly on lower-density lipoproteins.
It is believed that LCAT regulates the transport of cholesterol between extravascular pools. In the theoretical pathway, known as reverse cholesterol transport, cholesterol is moved from peripheral tissues to the liver for catabolism. The esterification of cholesterol by LCAT in serum serves to maintain a chemical concentration gradient for unesterified cholesterol between peripheral cells and the serum.
Plasma lysophosphatidylcholine (LPC) is 1 of the products of LCAT and as such, LPC concentration is diminished in patients with LCAT deficiency.
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.
CHOLESTEROL, TOTAL
The National Cholesterol Education Program (NCEP) has set the following guidelines (reference values):
Desirable: <200 mg/dL
Borderline high: 200-239 mg/dL
High: > or =240 mg/dL
Also see age and sex adjusted reference values in Total Cholesterol-Percentile Ranking in Lipids and Lipoproteins in Blood Plasma (Serum) in Special Instructions.
CHOLESTERYL ESTERS
60-80% of total cholesterol
Reference values have not been established for patients that are <16 years of age.
PHOSPHOLIPIDS
155-275 mg/dL
Reference values have not been established for patients that are <16 years of age.
LYSOPHOSPHATIDYLCHOLINE
16:0 Lysophosphatidylcholine: > or =62 mcmol/L
18:0 Lysophosphatidylcholine: > or =20 mcmol/L
Reference values have not been established for patients that are <16 years of age.
INTERPRETATION
No evidence of decreased lecithin cholesterol acyltransferase activity
Definitive results and an interpretive report will be provided.
Interpretation Provides information to assist in interpretation of the test results
Norum-Gjone disease is a severe form of lecithin cholesterol acyltransferase (LCAT) deficiency characterized by:
-Diminished serum levels of cholesterol ester (<50%)
-Increased serum levels of nonesterified cholesterol
-Increased serum levels of phospholipids
-Decreased concentration of lysophosphatidylcholine
-Decreased high-density lipoproteins (HDL)
-Increased triglycerides
Fish-eye disease, a less severe form of LCAT deficiency, generally demonstrates less severe changes in the parameters that are measured. Fish-eye disease appears to be specifically associated with esterification of HDL cholesterol.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
If lecithin cholesterol acyltransferase (LCAT) deficiency is suspected from initial tests, analysis of triglycerides and high-density lipoproteins (HDL) cholesterol will be performed at no charge. If fish-eye disease is suspected, percent cholesterol ester in the HDL fraction will be measured.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Norum KR, Gjone E: Familial serum-cholesterol esterification failure. A new inborn error of metabolism. Biochim Biophys Acta 1967;144:698-700
2. Carlson LA, Philipson B: Fish-eye disease. A new familial condition with massive corneal opacities and dyslipoproteinaemia. Lancet II 1979;2:922-924
Method Description Describes how the test is performed and provides a method-specific reference
See Individual Unit Codes
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.
Varies
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
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.
82465-Cholesterol, total
83789-Quantitative, each specimen
84311 x 2-Cholesterol esters and phospholipids
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 |
|---|---|---|
| PPL | Phospholipids, S | 2568-4 |
| CHLES | Cholesteryl Esters, S | 21197-9 |
| 83399 | 16:0 Lysophosphatidylcholine | In Process |
| TCS | Cholesterol, Total, CDC, S | 2093-3 |
| 23618 | 18:0 Lysophosphatidylcholine | In Process |
| 23859 | Interpretation | 59462-2 |
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