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Test ID: APT    
Activated Partial Thromboplastin Time (APTT), Plasma

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

The activated partial thromboplastin time assay results are determined by mixing patient plasma with HemosIL SynthASil reagent to provide optimal and uniform activation of the sample. After activation at 37 degrees C, the reaction is initiated by the addition of HemosIL SynthASil Calcium Chloride. The time, in seconds, required for the clot formation is then measured by the STA-R Evolution analyzer. The STA-R Evolution is a fully automated coagulation instrument that uses an electromagnetic viscosity detection system. The oscillation of a steel ball within the cuvette with the reagent and plasma is monitored by the STA-R Evolution. At the constant viscosity, constant pendular swings of the ball are obtained within an electromagnetic field. As the viscosity increases as a result of the coagulation, the oscillation amplitude of the ball swing decreases. An algorithm uses these variations in oscillation amplitude to determine the clotting time in seconds.(Package insert: HemosIL SynthASil, 2008; Operators manual: STA-R Evolution)

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.

Monday through Sunday; Continuously

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.

1 day

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

1 day

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

8 hours

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