human chorionic gonadotropin
human chorionic gonadotropin
|Analytical - Method:||two-site sandwich immunoassay using direct chemiluminometric technology|
|Reportable - Test Results Type:||Quantitative|
|Units - Conventional:||mIU/mL|
|Minimum Volume:||50 µL|
|Preferred Volume:||200 µL|
• Specimens with volume less than 50 µL are rejected as QNS with the appropriate message code. • Specimens that exceed the “Specimen Acceptability” stability but are within 7 days stability are treated with caution. • Specimens that exceed 7 days stability are rejected as NSA with the message code ML04: NSA due to age of specimen, greater than 7 days.
2. PROCEDURE PHLEBOTOMY 1) Wash hands thoroughly before beginning any phlebotomy procedure. Be sure to check expiration dates on tubes before proceeding. DO NOT USE EXPIRED TUBES. 2) Confirm the identity of the patient by checking at least two identifiers before collecting the specimen(s). This can be done by asking the patient to state their full name and requesting to see the patient’s driver’s license to verify picture, name, date of birth and/or drivers license number and documenting the information on the consent/chain of custody form. 3) Explain the procedure, including small risk of hematoma, slight pain, and some light-headedness. Inquire whether the patient has a history of fainting or dizziness with phlebotomy procedures so that ammonia inhalants can be obtained if necessary. Explain that loss of vacuum or a collapsed vein may necessitate another draw. 4) On a table or desk, assemble all necessary equipment: cotton balls and/or gauze, tubes, safety needle, alcohol swab, tourniquet, gloves, and band aid. Wearing safety gloves is MANDATORY. Wear additional protective equipment if contamination is expected. Safety needles should always be used; the only exception is if the patient is very hard to draw then a butterfly needle set may be used. 5) Position the patient so that they are seated comfortably in a chair with their arm extended on an armrest, desk, or table to form a straight line from the shoulder to the wrist. The patient’s arm and elbow should be firmly supported, and not bent at the elbow. 6) Check both arms to select the larger and fuller veins. Palpate and trace the path of the veins several times with your index finger. Tap the vein at the site of the draw with your index finger and second finger. This will cause the vein to dilate. The following factors should be considered in site selection: i) Extensive scarring. Healed burn areas or scar tissue should be avoided. ii) Specimens collected from an area with a hematoma may yield erroneous test results. If another vein site is not available, the specimen should be collected distal to the hematoma. 7) Apply the tourniquet. 8) Ask the patient to open and close his/her fist so their veins become prominent. Vigorous hand pumping is not necessary to activate blood flow and should be avoided. 9) Clean the venipuncture site with the alcohol swab in a circular motion from the center of the area to the outside. Allow the area to air-dry to prevent hemolysis and a burning sensation to the patient. 10) Insert the stopper of the first tube to be drawn into the adaptor. Do not push too far to avoid premature loss of vacuum via puncture of the needle. The recommended order of draw when drawing more than one tube is as follows: • Non additive tube (red stopper) • Coagulation tube (light blue stopper) • Serum separator tube (SST) or serum tube • Additive tube (lavender stopper, green stopper, etc) 11) Insert the needle into the vein with the bevel facing upward. Puncture the stopper on the tube by pushing it onto the end of the needle, and grasp the edge of the adaptor to provide stability once the blood flow has begun. Have the patient open his/her fist. 12) Fill the tube until the vacuum is exhausted. Remove the tube from the adaptor and insert subsequent tubes. Be sure that all tubes are completely filled to ensure sufficient blood sample for laboratory analysis. 13) Place a cotton ball or 2 x 2 square piece of gauze over the site. All used needles must be disposed of in a puncture proof biohazard receptacle. Never recap a needle. Recapping, purposeful bending, breaking, removing from disposable syringes, or other manual manipulations of needles is prohibited. Apply pressure to the site for 2-5 minutes. Place a band aid over the puncture site. 14) Again verify that the information on the sample tubes match the consent/requisition form. 15) Remove gloves and dispose of in a properly identified biohazard bag or container. Wash hands thoroughly after phlebotomy. ADDITIONAL VENIPUNCTURE CONSIDERATIONS 1) Prevention of Hematoma: a) Puncture only the uppermost wall of the vein b) Release the tourniquet before removing the needle from the vein. c) Use only major veins; not superficial veins d) Make sure that the needle fully penetrates the uppermost wall of the vein. Partial penetration may allow blood to leak into the soft tissue surrounding the vein by way of the needle bevel. e) Apply a small amount of pressure to the area with the cotton ball or gauze pad when bandaging the arm. 2) Prevention of Hemolysis: a) Mix anti-coagulated specimens thoroughly by inverting each tube gently 8 to 10 times. Do not shake. Vigorous mixing may cause hemolysis. b) Avoid drawing blood from an area with a hematoma. c) Ascertain that the venipuncture site is dry without touching it. 3) If a Blood Sample is Unobtainable a) Change the position of the needle. If the needle has penetrated too far into the vein, pull it back slightly. If it has not penetrated far enough, advance it farther into the vein. Rotate the needle a half-turn. b) Try another tube; the tube may not have sufficient vacuum. c) Loosen the tourniquet. It may be applied too tightly, thereby stopping the blood flow. Reapply the tourniquet loosely. This procedure can be accomplished easily when using the velcro-type tourniquet by releasing it and quickly pressing it together again. d) Probing for the vein is NOT recommended as it is painful to the patient. In most cases, another puncture in a site below the first site is advised e) Never attempt a venipuncture more than twice. Have another person attempt to draw the specimen. SPECIMEN HANDLING 1) Gently invert SST tubes 5 times and all tubes with anticoagulant (EDTA, heparin, etc.) 8 to 10 times. 2) Ensure all tubes are labeled with identification number and second identifier (printed first and last name for Insurance applicants). 3) Let red-top and marbled tubes clot, preferably in an upright position, for 10 – 20 minutes, but not more than 45 minutes. Centrifuge the tube for 5-10 minutes at 2500-3500 rpm and transfer the serum into a properly labeled pour-off tube using a disposable pipette. 4) Some other factors that can affect the sample are: a) Hemolysis. Hemolysis is defined as the breaking down of red blood cells. This can be slight, moderate or severe. The three (3) causes of hemolysis are TIME, TEMPERATURE AND TRAUMA. i) TIME: Holding blood over two (2) hours before centrifuging can and usually does cause some hemolysis. Allow at least 10-20 minutes, but no more than 45 minutes for the blood to clot prior to centrifuging. ii) TEMPERATURE: Never store blood in too warm an area; hot cars, hot sun, etc. Allowing blood to freeze in cold weather will also produce hemolysis. iii) TRAUMA: Going through the vein, accessing a collapsed vein, or using a needle that is too small can all cause hemolysis. The needles provided by the labs are usually 21 or 22 gauge. If a 23 gauge is used, it is very possible that hemolysis may occur. Only use a smaller needle when absolutely necessary. When doing finger sticks, DBS, etc., squeezing the finger is the main cause of hemolysis. b) Lipemia: Lipemia is defined as an abnormal amount of fat in the blood. This is usually caused by the patient not fasting.
|Collection Patient Preparation:||NA|
|Container:||• Collect all blood samples in serum separator tubes, observing universal precautions for venipuncture. • Allow samples to clot adequately before centrifugation|