Pre-analytical Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Pre-analytical and links to relevant pages within the course.
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| Pre-analytical Variables Pre-analytical variables are those that affect the specimen before the actual testing begins. Some of the pre-analytical variables to consider with molecular testing include those that are applicable to all clinical specimens but should be emphasized when discussing molecular methodologies; some of these include but are not limited to: Receipt of valid order Proper patient identification Proper venipuncture procedure for blood collection Use of correct anticoagulant Collection of correct specimen type (i.e.- plasma, serum, whole blood) Order of draw Proper storage Proper transport Procedures if there is a delay in testing and/or transport | View Page |
| Which of the following are examples of pre-analytical variables that affect molecular methodologies? | View Page |
| General Overview of Testing Tests for evaluating iron metabolism are generally used as initial or screening tests for hereditary hemochromatosis (HH) as they will detect the phenotypic expression of HH. These tests include serum iron (SI), transferrin (Tf) or total iron binding capacity (TIBC), serum ferritin (SF), and unsaturated iron binding capacity (UIBC).The serum ferritin assay is also used to assess the effectiveness of HH treatment.Molecular (DNA) analyses for HFE mutations are considered to be confirmatory tests for HH which may be ordered reflexively in patients with elevated iron results. Laboratories should establish their own reference intervals for assays of iron metabolism. In general, reference intervals vary by sex and by method used for the assays discussed in the following section. Typical reference intervals are included in the following sections for instructive purposes only and should not be used for evaluating actual patient data.The results of laboratory tests assessing iron metabolism should be interpreted with caution because a number of pre-analytical and physiologic factors can affect the results. Repeating elevated test results on fasting specimens is often advisable. | View Page |
| Joint Commission Patient Safety Goals Joint Commission adopted national patient safety goals for healthcare organizations, including specific goals for laboratories. 2009 Laboratory Services National Patient Safety Goals These goals are directly quoted. | View Page |
| American Society for Clinical Laboratory ScienceThe American Society for Clinical Laboratory Science, ASCLS, joins the leadership effort to prevent medical errors and increase patient safety. | View Page |
| Pre-analytical Errors Preanalytical Error What is it? How does it happen? What is the result? Hemolysis Red blood cells (RBCs) break and release contents of cell into plasma. Needle incorrectly positioned in vein; cells forced to squeeze through opening. Needle gauge too small; slow blood return into tube. Vigorous mixing or shaking of tube. Alcohol on skin that has not had sufficient time to dry. Some test results may be falsely elevated. (Potassium is especially affected by hemolysis.) Patient may have to be re-drawn. Clotted specimen Clumped or clotted cells in specimen that requires anticoagulated or whole blood Insufficient mixing of blood with anticoagulant in tube. Delay in mixing tube. Slow filling tube. Inaccurate test results for cell counts and clotting studies. Patient may have to be re-drawn. Tube filled to incorrect volume Too little or too much blood in tube. Tube removed from needle too quickly. Vacuum in tube has been compromised due to use of tube past the expiration date (Results in a short fill). Manual fill of tube may lead to over-fill. Test results may be unreliable due to dilution errors. Patient may have to be re-drawn. | View Page |
| What are Pre-analytical Errors? Pre-analytical errors are errors that occur prior to the testing process. Hemolyzed specimens, clotted specimens, incorrect tube type, and inadequate tube fill can all produce pre-analytical errors. Fortunately, many of these errors can be detected by the laboratory analyst so that corrections can be made before testing begins or before resulting and reporting the test. Unfortunately, the correction that needs to be made usually involves redrawing the patient. The table on the following page lists several preanalytical errors that can occur during the phlebotomy procedure. | View Page |