Chapter 15 Specimen Collection And Laboratory Procedures

1. Chapter 15 Specimen Collection And Laboratory Procedures

2. Microscope One or more lense that makes an enlarged image of an object.

3. Compound Microscope • Lets light pass through an object and then through two or more lenses.

4. Oculars • The ocular lens, also known as the eyepiece lens, is the part of a compound microscope that a user looks into to see a magnified image. It is a see-through double convex lens curved to cause images to appear larger.  • Monocular microscope has one eyepiece • Binocular microscopes have two

5. Objectives • The objectives are screwed into a circular revolving nosepiece that is revolved by hand

6. Objectives • Objectives are the lens farthest from the eye and closest to the specimen • A microscope has 3 to 4 objectives • 4x, 10x, 40x, 100x • Always begin focusing a microscope on the lowest power and then move to the next higher power and refocus

7. Objectives • The 4X objective is used for scanning a slide • This is lung tissue(pneumonia) 4X

8. Objectives • The 10X objective is used to count cells and to scan urine sediment • This is the most common objective. ALWAYSSTART WITH THE LOW POWER OBJECTIVE! Low power lens gives the widest field of view and makes it easier to find the specimen when you look through the microscope

9. Objectives • The 40X objective is used for red and white blood cell counts • This is a WBC

10. Objective • The 100X has the greatest power and is use to identify characteristics for bacteria and blood smears • Finding the specimen at high power, without first centering it in the field of view at low power, is nearly impossible.

11. 10X, 40X, 100X

12. Stage • The stage is the platform that holds the slide to be viewed • The hole on the stage allows light to enter from below, passing through the specimen to the lens system

13. Light • In order for the microscope to work, light must pass upward through the material being viewed and into the objective lens

14. How to use a microscope • Focusing the microscope is done by moving the objective up or down relative to the stage. Movement of the stage is controlled by the round knobs, on both sides of the microscope • This permits resting your arms on the table while focusing

15. Course and Fine Adjustments Knobs • The coarse adjustment focus knob moves the objective quickly(usually the larger knob) • It moves the tube and lenses closer and farther away from the specimen • This knob is used first to bring the specimen into focus

16. Course and Fine Adjustments Knobs • The fine adjustment knob is used to fine-tune the focus of your specimen after using the coarse adjustment knob. • It moves the objective much more slower with only a short distance. Focus slowly. It is easy to focus right past the correct focus point if you are going too fast. 

17. Eyepiece Adjustment • When using a binocular microscope, it is necessary to adjust the eyepieces to your own eye span and visual acuity. A gentle push inward or pull outward with adjust the distance between the eyepieces to accommodate your eye span

18. Light Adjustment • The right level of light is essential for a clear image. • Too little light will obscure details in darkness, while too much light will produce a blinding glare without the contrast necessary to distinguish features.

19. Putting It All Together • To focus the microscope for lab work using the 10X objective: • Maximum distance between the stage and objective • Clamp the slide on the stage • Turn on the light • Raise the condenser to its highest position • Look at the side not through the oculars, rotate the low-power-(10X) objective into position • Still looking for the side, use the coarse adjustment knob, lower the objective until it nears the stage or stops

20. Putting It All Together • Look through the eyepiece and reverse the direction of the course focus adjustment knob until the slide comes into focus • Adjust the fine focus until you attain the clearest possible image • Adjust the condenser(light source) until the image is clear • Slide the specimen with the mechanical knobs(left and right, toward or away from you)

21. Key Points • Start with the lowest power first • Always clip your objective(slide) in the center of the light source • Use the course adjustment knob(larger knob) to focus and move the stage(now you are done with this knob) • You can use the fine adjustment knob if needed(depending on your eyesight) • Then you can turn the nosepiece and use a higher power objective • Never use the course adjustment again(in the higher power) This will raise the stage and could crush the slide and break the microscope • Again only then will you use the fine adjustment knob to focus • Always put the objective back on the lowest power before you remove the slide and before you turn off the microscope • Cover the microscope

22. Microscope Care • The microscope is a delicate, expensive instrument that is easily damaged by dust, oil, light, and falls • Arm-part of the microscope is the part that you carry the microscope with on hand • Base-always support the microscope with the other hand underneath the base

23. Cleaning the microscope • Only clean your microscope lenses when they are dirty and only use lens paper • Blow dust form the glass with a syringe • Clean only the outside surface of the lens • Never touch the lens • Never substitute the lens paper(this may scratch the lens

24. Skin Puncture • Dermal puncture or capillary puncture: venipuncture is the most frequent performed phlebotomy procedure. • However, because current laboratory instruments and procedures enable us to use smaller and smaller amounts of blood, obtaining micro samples by capillary or dermal(skin) puncture is also popular • Always use the ring/middle finger

25. Fingerstick Sites • When performing a finger-stick, select a site on the central, fleshy portion of the ring or middle finger • The incision should be slightly off the middle of the finger and never to close to the nail bed • Avoid the index finger due to a large number of nerves(more painful) • The little(fifth) finger(decrease mass) • The thumb is too course (harder to obtain blood) Finger-sticks should not be performed on infants younger than 6 months of age due to the short distance between the finger bone and the skin surface.

26. Skin Puncture • Lancets are designed to control the depth of the dermal puncture • Safety lancets must be used, so that the blade retracts after use to prevent needle- stick injuries

28. Venipuncture • Venous:  venipuncture: surgical puncture of a vein • Phlebotomy Chair • For all blood collection procedures, the patient should be lying down or seated in a phlebotomy chair • In an outpatient setting, lock the arm mechanism, this prevents the patient from falling if the patient faints • It is critical to make the patient safe and comfortable during the procedure

29. Tourniquets • Tourniquets are used to help pool the blood in the veins, causing the veins to enlarge • In addition, the pooling of veins make it easier for the vein to tolerate the vacuum suction of the tubes withdrawing blood • Place the tourniquet on the patient’s upper arm, about 3 inches above the elbow • Ask about latex allergies • Disinfect the tourniquets with 70% alcohol after ever use • Never leave a tourniquet on longer than 1 minute(this can also alter blood test results) • If it is necessary to wait longer than a minute, remove the tourniquet and reapply it when ready • ALWAYS remove the tourniquet before removing the needle from the vein(this will cause a hematoma)

30. Common Sites for Venipuncture Venipuncture • Venipuncture method as called phlebotomy, take blood directly from a vein, most commonly in the antecubital area of the arm The inner arm at the bend of the elbow

31. Common Sites for Venipuncture Venipuncture • The vein used most often are the • Median cubital vein • Cephalic vein • Basilic vein • Other sites sometimes used are the lower forearm, back of hand and wrist

32. Antiseptics • 70 percent alcohol wipes(most common) • Alcohol prevents the introduction of microorganisms into the body during venipunture • It is critical when using alcohol to allow the alcohol to completely air dry • Betadine is the other antiseptic commonly used for blood alcohol levels, blood cultures, and blood donations

33. Butterfly Winged Infusion Collection Set • The butterfly winged infusion device consists of needle with plastic wings, plastic tubing, and an adapter • It’s easy-to-grasp and flexible • It can be attached to either a needle holder or a syringe • The needle gauge is usually 19 to 23 gauge and ¾ of an inch long • This can be helpful when collecting a specimen from a neonate, child, elderly, cancer patient, or severely traumatized patient

34. Butterfly Winged Infusion Collection Set • The butterfly winged infusion device consists of needle with plastic wings, plastic tubing, and an adapter • It’s easy-to-grasp and flexible • It can be attached to either a needle holder or a syringe • The needle gauge is usually 19 to 23 gauge and ¾ of an inch long • This can be helpful when collecting a specimen from a neonate, child, elderly, cancer patient, or severely traumatized patient

35. Butterfly Utilizing Tube System • When using a butterfly needle with an evacuated tube, use a 10 to 15 degree angle, this is slightly lower than the standard needle • With a butterfly set you can grasp the butterfly by the wings(easy to grasp)

36. Butterfly Winged Infusion Collection Set • When using a butterfly needle, you will know when the needle has entered the vein because you will observe a “flash” of blood on the shaft of the tubing • Patients may request the butterfly needle, because the length of the needle is shorter and looks smaller • Inform the patient that the gauge is about the same, therefore, there should no difference in pain with the two needles

37. Hematoma • Venipuncture must be always be done carefully to avoid causing an hematoma(collection of blood just under the skin) • To prevent a hematoma: • Puncture only the uppermost wall of the vein • Remove the tourniquet before removing the needle • Use the major superficial veins • Make sure the needle fully penetrates the upper most wall of the vein. (Partial penetration may allow blood to leak into the soft tissue surrounding the vein by way of the needle bevel) • Apply pressure to the venipuncture site

38. Methods Of Performing A Venipuncture • There are two methods of performing this procedure: • Syringe method • Needle and vacuum tube method

39. Syringe Draw • A syringe is a plastic barrel and plunger set that is manually pulled to control the flow of blood • Syringes come variety of sizes; 10 mL an 20 mL are the most commonly used in the venipuncture procedure(do not use any larger or smaller syringe) • Prior to attaching the syringe it is important to “prime” the syringe. Pull the plunger in and out of the syringe to ensure it moves smoothly • It is critical that the plunger be pushed back into place before beginning the phlebotomy procedure to avoid injecting air into the patient’s vein • You can control the rate at which the blood is being withdrawn • You should observe the vein during the procedure and make any adjustments to the rate of collection as needed (collapsed vein) • Once the blood has been collected in the syringe, you must engage the needle safety mechanism, remove the needle, and replace it with a transfer device before transferring the blood to the tubes. Allow the tubes to fill without applying pressure(this will hemolysis the blood)

40. Hemolysis • Hemolysis is the breakdown of red blood cells. • This can cause alterations to blood test results and give an inaccurate reading • Hemolyzes blood samples are generally discarded • Causes: • An improper choice in the venipuncture site • Prolonged tourniquet time • Cleansing the venipuncture site with alcohol and not allowing the site to dry • Pulling the plunger of a syringe back too fast • Transferring into a tube by pushing down on the syringe plunger in order to force blood into a tube • Vigorous mixing or shaking of a specimen • Having the patient pump their hand

41. Vacuum Method • This method is probably the most popular because it is so convenient

42. Gauge for Venipuncture • Gauge average size for venipuncture needles is 21 or 22 gauge in size

43. Blood Collect Tubes • A variety of different tubes are required when performing venipuncture. Tubes vary in size, volume, and additives • The color of the rubber stopper located at the top of the tube indicates what additive is found in the tube • Many tubes contain an anticoagulant, a chemical that interferes with the clotting process and prevents a clot from being formed in the tube

44. Blood Collect Tubes • These tubes have a “vacuum” a specified amount of air has been taken out by the manufacturer so that when the tube is pierced by the needle, the tube will fill with a predetermined amount of blood • This ensures that only the proper amount of blood enters the tube

45. Order Of Draw • When several blood specimens are ordered, they should be drawn into the color-coded stopper tubes in the order to prevent contamination from the additives in the other tubes • Yellow(for blood cultures) • Red/red-gray(no additive or anticoagulant is used) • Blue(contains the anticoagulant sodium citrate) • Green (contains one of three different anticoagulants: sodium heparin, lithium heparin, or ammonium heparin) • Lavender(contains the anticoagulant EDTA, which binds to calcium, preventing the formation of a clot) • Gray(contains two additives: sodium fluoride and potassium oxalate) • Young red-headed boys greet little girls

47. Explain What You Are Going To Do • It is important to explain what you are going to do • Ask the patient if they have any questions • Remember that you what the patient to feel comfortable and relaxed

48. Laboratory Classification And Regulation • POC: physician's office laboratory • Waived test: moderately complex tests(rapid strep's, UA) • Non-waived tests: complex tests with multiple steps(HIV) • CLIA: Clinical Laboratory Improvement Amendments: Law passed in 1988, establishing quality standards for all non-research laboratory testing performed on specimens derived from humans for the purpose of providing information for the diagnosis, prevention, treatment of disease, or impairment of, or assessment of health.

49. Hemoglobin And Hematocrit • Hemoglobin: is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues to the lungs • The HemoCue is one example of the instrument commonly used to measure hemoglobin with capillary blood

50. Hemoglobin • Hemoglobin is measured if anemia is suspected in the patient(usually along with hematocrit) • The normal range for females: 12 to 16 g/dl • The normal range for males: 14 to 18 g/dl