Laboratory Definitions
Not sure what specific lab terms are? We’ve listed out commonly used language here at the Diagnostic Lab.
| Term | Definition |
|---|---|
| Anticoagulants | Anticoagulants are used to prevent blood from clotting. To ensure accurate results, tubes must be filled to the appropriate fill lines or vacuum to allow for proper blood/anticoagulant ratio. Different types of anticoagulants are used for different purposes but the most common uses are: Hematology: EDTA to preserve WBC’s, RBC’s and platelets, Chemistry: Lithium heparin to allow for faster spin times on STAT chemistries |
| RTT | The Red-Top Tube does not contain anticoagulants or preservatives. They are typically used to collect whole blood for harvest of serum after clotting and centrifugation. This tube can be used to transport other body fluids not requiring anticoagulants or preservatives. |
| LTT | Lavender-Top Tube contains K2EDTA. Used for EDTA whole blood or plasma. |
| GTT | Green-Top Tube containing forms of heparin. Most chemistry analytes should be drawn into tubes with Lithium heparin. Sodium heparin may interfere with electrolytes and some other analytes. |
| Vacutainer | A sterile blood collection tube (glass or plastic) with a colored rubber stopper creating a vacuum seal. Stopper colors follow the standard vacutainer color-coding system for identification of additives. This will facilitate the drawing of a predetermined volume of liquid. This will also ensure the proper blood to anticoagulant ratio for hematology, chemistry, and coagulation testing. |
| Microtainer | These sterile blood collection tubes are used for collection whenever only the smallest amounts of blood are required or available. Tube cap colors correspond to the standard vacutainer color-coding system for identification of additives. Microtainers ensure the proper blood to anticoagulant ratio. |
| Dead Volume | The extra volume of serum or plasma required in the analyzer cup but not available by the probe. In our chemistry analyzer this is approximately 50 uL. |
| Whole Blood | Blood with all of its components (white cells, red blood cells, platelets and plasma) |
| Serum | Serum is the liquid part of the blood with similar components to plasma, but excludes the clotting factors. Tests requiring serum are drawn into a tube without anticoagulants. The blood is allowed to clot and centrifuged to separate the cells from the serum. The serum is removed from the cell button and transferred to a sterile tube (Eppendorf preferred) for chemical analysis |
| Plasma | Plasma is the liquid part of the blood in which white and red blood cells, platelets and other components of blood (fibrinogen, etc.) are suspended. Tests requiring plasma are drawn into a tube with the appropriate anticoagulant and centrifuged to separate the cells from the plasma. The plasma is transferred into a transport tube (sterile Eppendorf preferred) for analysis |
| EDTA | A strong anticoagulant used in lavender-top tubes which confers preservative benefits for cellular morphology. The EDTA chelates calcium present in the blood, arresting the coagulation process. It is the anticoagulant of choice for hematology specimens such as CBC and platelet counts |
| Lithium Heparin | An anticoagulant activates antithrombins, blocking the coagulation cascade. It is mostly used for STAT chemistries by allowing for faster centrifugation times. |
| Sodium Heparin | An anticoagulant that interrupts the coagulation cascade, for electrolyte analysis this type of anticoagulant is inappropriate and will cause inaccurate sodium levels. |
| Dilution | Dilutions are expressed as the ratio of the quantity of a desired solute (serum, plasma, urine, chemical solution etc.) contained in a solvent (diluent). Dilutions are performed on samples with insufficient amount or if concentration/result is too high. Dilutions will reduce the concentration which will decrease accuracy of result. Place on request form if dilution is acceptable for your results. However, only some analytes can be diluted, so please contact the lab if your analytes can be diluted. |
| Priority List | If your submitted sample has an insufficient quantity required for testing, we request a priority list for your submission. Please create a list of your analytes from most to least important. |
| Labeling | Clearly label your samples prior to submission and include the preferred patient name you would like on the final report. Sample source must also be included on submission forms or specimen container. |
| Fill line | All vacutainer tubes indicate a fill line or required volume on the tube. Over or under filling will decrease quality or alter results. Please note the fill line requirement prior to obtaining sample. |
| Vacuum | Vacutainer blood collection tubes facilitate the drawing of a predetermined volume of liquid required for quality testing. If the vacutainer is old, or if the seal has been broken, the vacuum will decrease. By putting pressure on the plunger to inject the sample into the vacutainer, it can damage the cells. Please allow vacutainer to naturally fill to required fill line. |
| Aerobic transport media | Charcoal Amies swab or Eswab used for aerobic cultures in Microbiology |
| Anaerobic Transport media | A swab that is specifically used to transport culture specimens for anaerobic culture. |
| Culturette swab | A variety of swabs containing bacterial transport media used for microbiology culture specimens |
| Sticky Swab | Swabs with a unique pink “sticky” fur tip. These swabs are preferred for C. bovis PCR. |
| Blood Culture Bottle | A special collection tube with broth media to enrich growth of microorganisms in blood. Signal blood culture bottles can detect both aerobic and anaerobic microorgaisms with as little as 1mL of blood. |
| Eswab | Combines a flocked swab with 1mL of Amies liquid solution for optimal recovery of aerobic and anaerobic organisms from a variety of clinical samples for microbiological analysis |
| Cell Line Instructions | Any biological material (rodent, human, cell lines, parasites, protozoa, viruses including viral vectors, etc.) should be tested for rodent pathogens prior to use. See Biological Materials testing protocol and submission form. LINK |
| Cytospin | A technique using high speed centrifugation to concentrate and deposit cells uniformly on a slide for microscopic analysis |
| Hemogram | A CBC (Complete blood count) which includes: WBC count, RBC count, hemoglobin, hematocrit, Indices, Red cell distribution width (RDW), and platelet count. |
| BTT | A blue topped tube is commonly used for coagulation testing. Includes an additive Sodium Citrate, and insufficient blood collection volume yields to elevated clotting times. |
| Buffy Coat | The layer of white cells and platelets that forms between the serum and blood cells in a centrifuged whole blood sample. |
| uL | Microliter, a SI unit of fluid measurement, equal to 10-6 liters |
| mL | Milliliter, an SI unit of fluid measurement, equal to 10−3 liters |
| Clotting | The process in which blood changes into a solid state, forming a thick mass called a clot. |
| Aseptic technique | Refers to collected samples with a sterile technique to avoid contamination during collection. Examples include: handwashing prior to collection, cleaning collection sites, and using alcohol to clean the septum of blood culture bottles or red-top tubes prior to injection of blood or body fluids, respectively. |
| Analytes | A chemical constituent in clinical chemistry that is of interest in an analytical procedure |
| Biological Material | Any biological material (rodent, human, cell lines, parasites, protozoa, viruses including viral vectors, etc.) should be tested for rodent pathogens prior to use. See Biological Materials testing protocol and submission form. LINK |
| Stat | A laboratory test that is required to immediately treat a patient. Stat tests are to be performed prior to other samples in the queue. |
| Rinse syringe | Rinsing the syringe with appropriate solutions of either EDTA (preferred for hematology) or lithium heparin will help prevent the clotting in rodent samples. Draw up solution, coat the walls of the syringe and expel all solution out. Care must be taken to not over dilute the blood with anticoagulant. Record the anticoagulant used on your request form. |
| Hemolysis | A pathological process that breaks down red cells and causes varying tinges of red to permeate the serum/plasma once it has been centrifuged. Hemolyzed specimens may give inaccurate results for many different laboratory tests. |
| Lipemia | A lipemic sample is one that contains such a high amount of emulsified fats in the serum/plasma that it becomes cloudy. Lipemia can affect laboratory results. |
| Icterus | A sample is icteric when the serum or plasma is deeply yellow or brownish. Common causes of icterus are liver damage and rapid breakdown of red blood cells and clinically associated with jaundice. |
| Smudge Cell | WBC’s that are fragile and appear to be smudged when they are spread on a slide and stained. This can be due to a disease process or some sort of pre-analytical condition such as prolonged storage, storage directly on ice/icepacks, exposure to heat or formalin, etc. |