Method Description Describes how the test is performed and provides a method-specific reference
The plasma specimen is hydrolyzed with 2% potassium hydroxide (KOH)/ethanol for 1 hour at 65 degrees C. The compounds are then extracted with hexane, followed by evaporation to dryness under nitrogen. Using 50:50 N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA):pyridine, the sterols are derivatized to generate trimethylsilyl ethers. The derivatized specimens are then transferred to gas chromatography (GC) sampling vials and 2.0 mcL is injected onto a HP-5 capillary column. Selected ion-monitoring electron impact gas chromatography-mass spectrometry (GC-MS) is used to quantitate desmosterol, lathosterol, campesterol, and sitosterol in the reference range. Quantitative analysis in specimens with increased sterol concentrations (>10 mg/L by GC-MS) is accomplished using gas chromatography-flame ionization detection with epicoprostanol as the internal standard.(Kelley RI: Diagnosis of Smith-Lemli-Opitz syndrome by gas chromatography/mass spectrometry of 7-dehydrocholesterol in plasma, amniotic fluid and cultured skin fibroblasts. Clin Chim Acta 1995;236:45-58)
PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information
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; 2 p.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