Phlebotomy Tubes

EDTA is an

anticoagulant. Ethylenediaminetetraacetic acid (EDTA) is a chelating agent in lavender top blood collection tubes that binds calcium, an essential component for human blood coagulation. It is valuable as an additive as it prevents whole blood from clotting in vitro (i.e., inside the tubes), which is preferential for a variety of medical laboratory tests.

The appropriate needle gauge to use for most venipuncture collections is

21.

Which patient description is correctly matched with the appropriate site selection

A 53-year old male with a central line has a specimen collected from the dorsal side of the hand. Rationale Patients with central lines would be candidates for specimen collection from dorsal side of the hand. Venous samples are not collected from the palmar side of the wrist; veins are accessible from the dorsal side. Fingersticks are not performed on newborns as the blade depth could injure nerves in the fingertips and blood would be difficult to extract. Heel sticks may be performed on newborns, but not in the central section of the plantar surface. Nerve and/or tissue damage could result.

Which of the following tubes should the medical assistant select in collecting a blood sample for a Complete Blood Count (CBC)?

A CBC is performed on a whole blood sample. It should be collected in a lavender top tube containing ethylenediaminetetraacetic acid additive as an anticoagulant. Blue top tubes contain sodium citrate anticoagulant and are commonly used for coagulation studies (PT, PTT, etc.). Green top lithium heparin tubes are commonly collected for chemistry tests that can utilize plasma. Specimens collected in red top tubes containing no additive will clot and form serum (commonly used for chemistry and serology testing requiring serum).

A test tube with which of the following colored stoppers has a glycolytic inhibitor?

A gray top blood collection tube contains powdered sodium fluoride and/or potassium oxalate, which will inhibit glycolysis. Glycolysis involves the breakdown of sugar to produce energy. As an example, gray top tubes are used to collect blood samples for glucose tolerance tests because if any glucose present in the patient's blood would need to be preserved until tested; if the glucose were allowed to be broken down during processing (i.e., by the cells that metabolize it), the laboratory tests would not be able to measure the full amount present in the patient at the time of collection. The glucose value would be lower in vitro (in the lab) than in vivo (in the body of the patient).

Which of the following evacuated tubes should the medical assistant select for collection of electrolytes?

A green top tube contains heparin. Green tops are used for collection of heparinized plasma or whole blood for special tests. Note: After the tube has been filled with blood, the tube is inverted several times to prevent coagulation. Note: Green top tubes can contain ammonium, lithium, and sodium in addition to the heparin. In this instance, lithium heparin would be the green-top of choice (and sodium heparin would NOT be used for an electrolyte test). Electrolytes can also be collected in a red-top tube.

Which of the following types of additives is present in an EDTA tube?

An EDTA tube contains the anticoagulant sodium ethylenediamine tetra-acetic acid, which prevents clotting. Red top tubes can be plain or have gel separators. Plastic red top tubes can contain a clot activator to expedite the clotting process. Common blood collection tubes are already sterile, thus don't contain antimicrobial additives.

Which of the following additives protects serum from interacting with red blood cells after a specimen has been centrifuged?

Gel separators create a barrier between the serum and formed elements of the blood. Prolonged contact of serum with formed elements can lead to pre-analytical variations in certain tests (such as serum glucose levels). Tubes with clot activators, such as thrombin, actually expedite the clotting process. Anticoagulant tubes keep the blood from clotting, yielding plasma instead of serum. Sulfosalicylic acid is used in urine testing to precipitate proteins.

Which of the following tests is drawn in an EDTA tube for the hematology department of the laboratory?

HGB HGB is an abbreviation for Hemoglobin, typically measured as part of a Complete Blood Count and collected in an evacuated tube containing Ethylenediaminetetraacetic acid (EDTA). Hemoglobin is a protein inside red blood cells that carries oxygen to organs and tissues, while also transporting carbon dioxide back to the lungs. BMP = basic metabolic panel (common screening panel with tests for renal function, electrolyte balance, glucose, and more) HCG = human chorionic gonadotropin (pregnancy test) PTT = partial thromboplastin time (a common test for coagulation abnormalities or to monitor patients on heparin therapy)

A phlebotomist is staffing the outpatient clinic at a remote site. There is a centrifuge at the site, but it is not functional. The courier will be arriving to pick-up all samples collected at 1300, and will deliver to the testing laboratory at 1500. A patient arrives at 1200 with orders for Complete Blood Count, Prothrombin Time, and Basic Metabolic Panel. Which tubes should the phlebotomist use for blood collection?

Lavender, Blue, Green, Gray Of the answer options provided, the best answer would accommodate testing accordingly: Complete Blood Count (CBC) = lavender top tube (EDTA) Prothrombin Time (PT)/INR = light blue top tube (sodium citrate) Basic Metabolic Panel (BMP) = green top tube (heparin); since the centrifuge is not functional and there is a bit of a delay between draw time and courier pickup/delivery to the laboratory, a gray top tube would best preserve the glucose value within the BMP.

A physician asked you to draw a INR on Mr. Jones which tube and additive would you choose

Light Blue, Sodium Citrate An INR test refers to an International Normalized Ratio, which provides a standardized method of reporting prothrombin time results by comparing the ratio of the patient prothrombin time to the control prothrombin time. This, in turn, helps to standardize the method of reporting the effects of oral anticoagulant therapy on blood clotting. It uses the light blue tube with sodium citrate as it would for a regular prothrombin time (Pro Time) test.

Which of the following tests monitor anticoagulation therapy?

PT and PTT are coagulation tests (collected in blue top tubes). They are routinely collected to monitor a patient's anticoagulant drug therapy (to make sure that the dose the patient is taking provides the proper effect, but does not dangerously over-anticoagulate and introduce a critical risk of bleeding). In short, these tests monitor a patient's blood clotting time. T3 and T4 are thyroid tests. Hgb and Hct reflect the amount of hemoglobin in the red blood cells and the number of red blood cells per volume of whole blood (hematocrit). ABO and Rh are blood typing tests that determine a patient's blood group.

Which of the listed tubes can contain ethylenediamine tetraacetic acid?

Royal blue blood Collection tubes may be purchased with EDTA, sodium heparin, or no additive at all. They are used for trace element testing via plasma or whole blood. They can also be used for toxicology and nutritional studies. The most common tubes that contain EDTA are lavender top/light pink tubes.

The phlebotomist is drawing plain red, lavender, and blue top tubes. Upon completion of the blood draw, the phlebomist noticed that an order that requires a SST has been missed. What would be the next action?

Share the plain red top specimen for the SST test A plain red tube and an SST tube both will yield serum once clotted and centrifuged. Therefore, it is possible to share the plain red top specimen for the SST test. There is no need to re-stick the patient. The lavender and blue top tubes both contain anticoagulant, thus they produce plasma (not serum) when centrifuged. They would not be good substitutes for an SST specimen.

A patient is at the lab for their weekly PT/INR. Which of the following tubes should the medical assistant collect for this test?

Sodium citrate (light blue top tube) is the anticoagulant of choice for coagulation studies such as PT/INR (Protime/International Normalization Ratio) because it does not bind to calcium or inactivate heparin, which may be required to be present in such testing. Lavender top tubes contain EDTA as the anticoagulant, which does bind calcium. Green top tubes contain heparin and could lead to inaccurate coagulation studies.

The physician orders a sedimentation rate for a patient recovering from an infection. This is indicated on the lab requisition as which of the following?

The Erythrocyte Sedimentation Rate (ESR) is a common test to detect inflammation by measuring the rate at which red blood cells settle to the bottom of a tall, thin tube. Since inflammation can cause cells to clump, these clumps are heavier than single cells and settle more quickly. The test measures the distance settled in one hour. This test is most useful in combination with other more specific laboratory tests. EBV = Epstein Barr Virus (causes a number of diseases, including infectious mononucleosis) CRP = C-Reactive Protein ( appears with inflammation in the body) INR = International Normalized Ratio (a measure of coagulation)

Identify the CLSI recommended micro-collection order of draw for a BMP, CBC & Bilirubin.

The recommended Order of Draw for capillary blood collection is different from blood specimens drawn by venipuncture. CLSI recommends the following order of draw for skin puncture: Blood gases, EDTA tubes, Other additive tubes, then Serum tubes.

When a complete metabolic profile (CMP) and complete blood count (CBC) are ordered at the same time, why should the CMP be drawn first?

Tubes without additives should be drawn before tubes with additives. A blood specimen will naturally clot (yielding a serum component) when collected in a tube without an additive to anticoagulate it and keep it whole blood (which has a plasma component). With the exception of blood cultures and coagulation tests (e.g. PT, PTT), serum tubes (for CMP, Lytes, etc.) should be collected before tubes with additives (e.g. lavender top for CBC) to avoid contamination of the serum tube with the additive (can cause erroneous results in the serum tube). CLSI lists the order of draw as follows: 1. Blood cultures 2. Coagulation tube (e.g. blue closure) 3. Serum tube with or without clot activator, with or without gel (e.g. red closure) 4. Heparin tube with or without gel plasma separator (e.g. green closure) 5. EDTA tube with or without gel separator (e.g. lavender closure, pearl closure) 6. Glycolytic inhibitor (e.g. gray closure)

A phlebotomist is asked to collect a CBC, PT and Chem 7 on a patient that requires a hand stick with a butterfly needle into evacuated tubes. The correct order of draw for this collection would be

Two Light Blue Top Tubes, Green Top Tube, Lavender Top Tube The correct order of draw would be: two light blue top tubes (one waste and one for PT which is a coagulation test), green top tube (for the Chem 7), and the lavender top tube (for the CBC).

Filling evacuated tubes to the indicated level results in the correct ratio of

additive to blood Blood collection tubes are medical devices and manufacturers' directions for use must be followed as for any other medical devices. This is particularly crucial with respect to any stated minimum fill line for tubes with additives. If too little blood is drawn in a tube with an additive, the ratio of additive to blood is higher than expected. Insufficient sample volumes produce "relatively" elevated levels of the additives in the sample collected. There is simply too much additive for the amount of blood in the tube. Here are just a few examples of problems: Relatively elevated levels of EDTA (which binds calcium to prevent clotting) can bind too much calcium and begin binding other elements in the blood, which can affect several laboratory tests. Too much heparin per blood volume can produce negative anion gaps, slow antigen-antibody reaction rates, falsely low albumin levels, and significantly higher CK (creatinine kinase) levels.

Which of the following specimens is most susceptible to cross contamination and should always be drawn first?

blood culture Since blood cultures test for sepsis (infection in the blood stream), the skin should be specially prepared to avoid contaminating the specimen during the collection process with normal skin bacteria. The exact preparation protocol may vary slightly among services, but most phlebotomy procedures will either use an iodine solution, ChloraPrep, or equivalent chlorhexidine-based skin antisepsis solutions. When blood cultures are ordered along with other laboratory testing, collect the blood cultures first. The regular alcohol pre-draw prep is sufficient for the CBC, cholesterol, and hematocrit (HCT can be ordered separately, but is included within a CBC).

The physician has ordered a prothrombin time (PT) and complete blood count (CBC) for an adult patient with a diagnosis of thrombophlebitis. The medical assistant should collect the evacuated tubes in which of the following orders?

blue, lavender n the past, there was concern that the first blood collected into a tube or syringe was contaminated with tissue thromboplastin resulting from the entry of the needle into the skin. The presence of tissue thromboplastin in a blue top tube could alter the results of the routine coagulation tests, protime (PT) and activated partial thromboplastin (aPTT). Therefore, it was necessary to collect a small quantity of blood in another tube to assure that no tissue thromboplastin would contaminate the blue top tube. Research now indicates that the amount of tissue thromboplastin generated from a venipuncture today is minimal and will not affect the results of PT and aPTT testing. However, studies have not been performed for other coagulation tests so a discard tube should be filled with a small volume of blood prior to collecting blood into a blue top tube. NOTE: The "no discard tube needed" policy applies only when using a routine venipuncture with needle/tube holder or needle/syringe. A lavender (EDTA) tube is the appropriate tube to collect for a CBC test. CLSI (Clinical and Laboratory Standards Institute) lists the order of draw as follows: 1. Blood culture tube 2. Coagulation tube (eg, blue closure) 3. Serum tube with or without clot activator, with or without gel (eg, red closure) 4. Heparin tube with or without gel plasma separator (eg, green closure) 5. EDTA tube with or without gel separator.

When collecting specimens for alanine aminotransferase (ALT) or aspartate aminotransferase (AST), avoid gray-topped sodium fluoride tubes because the anticoagulant

destroys many enzymes. The sodium fluoride in gray-topped tubes can destroy many enzymes. Since ALT and AST are enzyme tests, sodium fluoride should be avoided.

A physician has ordered STAT blood work for a patient. The tests ordered are Hgb/Hct, chemistry panel, and PT test. Which of the following tubes are needed for this procedure? (Select the three (3) tubes that apply.)

lavender, light blue, red Rationale: The medical assistant should draw the following tubes: Lavender for the Hgb, Hct Red for serum chemistry test Light blue for the PT (Yellow is used for blood cultures and gray is generally used for glucose samples.) CLSI lists the order of draw as follows. 1. Blood culture tube 2. Coagulation tube (blue closure) 3. Serum tube with or without clot activator, with or without gel (red closure) 4. Heparin tube with or without gel plasma separator (green closure) 5. EDTA tube with or without gel separator (lavender closure, pearl closure) 6. Glycolytic inhibitor (gray closure)