|Bone Marrow Aspirate and Biopsy Collection|
Some pathologists prefer their bone marrow smears to be made fresh at bedside without the use of any anticoagulants. This however limits the number of smears that can be made before the sample clots. Using a syringe, that has been rinsed with preservative-free heparin, to pull the marrow during the procedure will prevent clotting but will introduce morphology changes and staining artifact.It is preferable to make smears as soon as possible after sample collection. However, when stored in the refrigerator, acceptable smears can be made from an EDTA tube as long as 8-10 hours after sample aspiration without introducing excessive amounts of artifacts. This is useful when marrows are collected at times when staffing trained in marrow smear preparation may not be available.
|Long Slide Preparation Techniques: T-prep|
The T-prep technique is a simple pull preparation method, which produces one readable long slide for each drop of marrow used. It does not require much manual dexterity or practice to obtain usable smears. Since this method only produces one usable smear per drop and requires a moderate size drop of marrow, it is not a preferred technique for small samples. However, it is easy to learn and is frequently used by clinicians.To perform this procedure, a drop of bone marrow is placed in the center of a slide (cross bar) and a second slide (post) is placed over it; oriented so the combination looks like the letter t. The marrow is allowed to spread between the two slides while the slide that is on the top (post slide) is pulled across the bottom slide (cross bar). This produces one slide with the bone marrow smear on the top slide. The bone marrow smear should cover approximately 3-4 inches in length.This technique can be performed sequentially with a series of 5-6 slides in a row with a drop of marrow quickly placed on each slide. The bone marrow drops can originate directly from the aspirate syringe at the patient bedside or from a transfer pipitte, collecting sample from an anticoagulated bone marrow tube. Once the first smear is made, the slide that initially had the drop of marrow becomes the top (post) slide for the next prep. By reusing the bottom slide, which no longer has any sample on it, one can minimize the amount of workspace required at bedside as well as reduce material wastage. Because the bone marrow is allowed to spread between two slide surfaces before the prep is pulled/smeared, any spicules present will be spread in a monolayer permitting good cellular identification. However, since only a limited number of smears are usually made, it is less useful for certain leukemia patients where many slides are required for special stains in addition to the normal morphology smears.
|Long Slide Preparation Techniques: Pull Prep|
A long slide pull preparation, or pull preparation, is a variation of the T-preparation. This method results in shorter smears than the T-preparation but produces two smears for each drop of bone marrow.In this method, a drop of bone marrow is place in the center of a slide while a second slide is placed directly on top with as much overlap as possible. The idea is to leave only enough of the edges revealed to allow the preparer to grip the slides for the pulling of the smear. Once the bone marrow has spread toward the edges, the two slides are slowly slid apart, forming a 1-2 inch smear on both the top and bottom slides. This method provides more smears per volume of bone marrow used, but is a bit more difficult to use without regular technique practice. The placement of the drop of marrow is critical to obtaining two usable smears from each pulled smear. Pull preps can be made at the patient bedside from a syringe or from an anticoagulated bone marrow sample.
|Bone Marrow Collection: Patient Bedside|
When the technologist accompanies the clinician to assist with the bone marrow aspiration procedure to make smears at the bedside, it is necessary to understand the role of the clinician and the technologist.The clinician is responsible for patient positioning and sterile preparation, pain control, and performing the aspirate and biopsy. The clinician often hands off sample syringes to the technologist, once collected. The clinicians are responsible for providing the procedure kit and fixative for the biopsy, all labels, and obtaining the requisitions and a copy of the clinical history for the hematopathologist. The technologist will set up a mini workspace near the bedside where the samples are split into the required tubes. Smears are then prepared from the aspirate as well as biopsy touchpreps before the biopsy is placed in fixative. In this setting the technologist will usually deliver the samples and requisitions to pathology and continue the processing procedure.The kit the technologist brings to the bedside usually contains mini petri dishes, coverslips, slides, microcapilary tubes or Pasteur pipettes, micro-pipette bulb and the various evacuated blood collection tubes and media flasks required for the standard bone marrow draw.Most institutions will have a standard draw and testing protocol designed to ensure that enough sample is obtained to cover all of the usual testing requirements. An example would be a three-syringe-draw with the first two syringes containing no anticoagulant and the third syringe rinsed with preservative-free heparin. The first dry pull would be split between a green and a purple top evacuated blood collection tube and would be used for morphology (EDTA) and flow cytometry and cytogenetics (green) if needed. The second dry pull is split into two additional purple top tubes plus a green top tube and would be used for molecular assays such as SNP array, Flt-3, JAK2, MPL mutation, etc. The final heparinized syringe could be used for other treatment protocol requirements or to provide sample for additional assays.
Hemolysis can easily be caused by improper phlebotomy techniques. Hemolysis occurs when RBCs are broken up and hemoglobin is released into the plasma, causing it to become pink rather than its natural straw color. Hemolysis can occur by using too small a needle, pulling a syringe plunger too rapidly, expelling blood vigorously into a tube, or shaking a tube of blood too hard. Hemolysis can cause falsely increased potassium, magnesium, iron, and ammonia levels, and other aberrant lab results.In this case, Marcie did not properly wipe the site with gauze after cleaning it with alcohol, and alcohol contacting the blood could have caused RBCs to break up or hemolyze. Marcie also squeezed the baby's foot too hard, causing hemolysis.Relevant topics:Site selection and preparation, Heelstick: Puncture, Hemolysis, Causes of hemolysis
|What could have caused the clotting?||View Page|
Tubes are drawn in a specific order to avoid the possibility of erroneous test results caused by carryover of an additive from one tube to the next. If a blood culture is ordered, it should be drawn as the first tube. Additional tubes should follow this order of draw. Sodium citrate - coagulation tube (light-blue top) Serum tube - with or without clot activator or gel. This tube is either a red top tube or a gold top tube depending on manufacturer and tube additive. Sodium or lithium heparin with or without gel plasma separator (green top) Potassium EDTA (lavender or pink top) Sodium fluoride, and sodium or potassium oxalate (gray top)
|Single draw needles|
Single draw needles are of the type that fit on a syringe, and can be used only to fill the syringe to which they are connected.
|Syringes with built-in safety devices|
Syringes are used for injections, as well as to collect blood.
There a various syringes with built-in safety features.One example is the Monoject™ (Sherwood Services AG), Safety Syringe, shown here.
|Syringes with built-in safety devices contd.|
After use, a safety shield is slid over the needle, and locked into place.
The safety syringe with the shield locked in place is shown here.
|Blood transfer device|
A blood transfer device allows the transfer of blood from a syringe into a blood collection tube or a blood culture bottle.
The BD™ blood transfer device is shown here.
|Butterfly needles continued|
Butterfly needles may be used with a syringe or a holder and vacuum collection tube system.
They are usually 21, 23, or 25 gauge.
|Syringe - Syringe blood collections|
Syringes may be used to collect blood from patients having small or delicate veins that might be collapsed by the vacuum of the evacuated tube system.Syringes may also be used to collect blood culture specimens.
|Syringe - Syringe blood collections continued|
Syringes may be used in two ways:Syringes may be used in two ways:A syringe may be attached to a butterfly or winged infusion set.
|Syringe - Transferring blood to collection tubes|
After collecting the blood specimen into a syringe, properly activate the appropriate safety device, and dispose of the needle in a sharps container.Attach the syringe to a blood transfer device by twisting the needle tip into the hub of the device.Push a vacuum blood collection tube into the holder of the transfer device, and let the tube fill to the appropriate level.
|Syringe - Transferring blood to collection tubes contd|
It is important to transfer the blood to appropriate tubes immediately because a syringe contains no anticoagulant, and the transfer must be complete before blood starts to clot.Do not push the plunger while transferring blood into a collection tube.
This may cause hemolysis, ruining the specimen.
|Butterfly needle - Butterfly needle collections continued|
Butterfly needles come attached to a small tube which may be connected to:An evacuated tube holder, orA syringe.
Blood for culture can be collected in several ways:Standard needle attached to a syringe.Butterfly needle attached to a syringe.Blood culture bottle attached directly to tube holder (not generally recommended).Follow you own facilities' procedure for blood culture collection.
|Activate needle safety device|
After collecting the blood, activate the needle safety device according to manufacturer's instructions, and place it in a sharps disposal container.
If blood was collected into a syringe, insert the syringe tip into the hub of a blood transfer device, and rotate the syringe clockwise to secure it to the device.
Push the blood culture bottle into the holder of the transfer device, and draw the appropriate volume of blood into the blood culture bottles.
|Causes of hemolysis|
Hemolysis can be caused by: Shaking the tube too hard.Using a needle that is too small.Pulling back too hard on a syringe plunger.Pushing on a syringe plunger too hard when expelling blood into a collection device.
|Causes of clotting|
Clotting can be caused by: Inadequate mixing of blood and anticoagulant within the collection tube.Delay in expelling blood within a syringe (which contains no anticoagulant), into a collection tube with anticoagulant.
|Do Not Tamper With the Specimens|
A phlebotomist should not uncap a blood tube and pour blood between tubes or combine two partially filled tubes of blood into one. This may lead to over-fill of tubes and more importantly, invalid patient results. Combining two tubes with the same additive into one tube will alter the blood to anticoagulant ratio by doubling the amount of anticoagulant in the tube. When blood is being transferred from a syringe to a tube, the phlebotomist must not apply pressure to the plunger to force blood into the tube. This may cause over-filling of the tube and hemolysis of blood cells. With the aid of a transfer device, the tube will draw the amount of blood required to fill the tube based on the amount of vacuum in the tube.
The syringe and needle combination should be the last equipment option that is considered; it is not as safe a choice as the self-contained blood collection systems because it involves more manipulation. However, the phlebotomist may choose to use a syringe to prevent vein collapse if the phlebotomist thinks that the vein is too fragile to withstand the pressure exerted by the vacuum as it pulls blood into the collection tube. A transfer device aids in the safe transfer of blood from the syringe into blood collection tubes. During blood transfer, do not manually push plunger as this may cause hemolysis of the specimen.
The winged device is another popular choice for the phlebotomist. This may be chosen for pediatric venipuncture, small delicate veins on adults (particularly geriatric patients), or hand veins. The device can be used with a needle holder and evacuated tube or a syringe. A needle safety device is incorporated into the design of the winged device to prevent needlestick injury.
|Handle With Care|
Equipment: To successfully enter a hand vein, the phlebotomist must choose equipment that will allow needle entry at a very small angle. A winged device with a small gauged needle of 3/4 inch length is most often used to obtain blood from a hand vein. A syringe is usually attached to the end of the tubing of this device. By using a syringe, the phlebotomist can control the amount of pressure on the vein and avoid vein collapse. Evacuated tubes may collapse a vein by exerting too much pressure on the delicate vein. If available, smaller tubes containing less vacuum may be used.Insertion angle: The angle at which the needle is inserted into a hand vein is smaller compared to the angle of needle insertion into veins of the antecubital area. When drawing from a hand, the needle should be inserted into the vein at approximately a 15 degree angle to allow easier access of the surface hand veins. By inserting the needle at this angle, the risk of the needle going "through" the vein and puncturing the bony structures underneath are reduced.