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Test ID: PTHFN    
Parathyroid Hormone, Fine-Needle Aspiration Biopsy (FNAB)-Needle Wash

Method Description Describes how the test is performed and provides a method-specific reference

The saline needle-wash specimen is analyzed with the Roche Diagnostics PTH reagent assay performed on the Roche Cobas 6000. The Roche Cobas assay for determining intact parathyroid hormone (PTH) employs a sandwich test principle in which a biotinylated monoclonal antibody reacts with the N-terminal fragment (1-37) and a monoclonal antibody labeled with a ruthenium complex(a) reacts with the C-terminal fragment (38-84). Application of a voltage to the electrode then induces chemiluminescent emission, which is measured by a photomultiplier. The antibodies used in this assay are reactive with epitopes in the amino acid regions 26-32 and 37-42.(Package insert: Roche PTH reagent, Roche Diagnostics Corp, Indianapolis, IN July 2010)

For all samples with PTH concentrations >40 pg/mL, a dilution series is performed. A linear dilution excludes hooking and most major interferences. Samples that contain PTH concentrations <40 pg/mL are spiked with exogenous PTH to identify possible interferences that may cause a false-low result.

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.

Monday through Friday; 5 a.m.-12 a.m., Saturday; 6 a.m.-6 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.

Same day/1 day

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

3 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

3 months

Performing Laboratory Location The location of the laboratory that performs the test

Rochester