Capillary puncture: processing, legal, and professional issues

Specimen handling

Capillary collection containers are often too small for a label to be applied to the tube. The most efficient way to transport capillary tubes is to remove the stopper from a red-topped venipuncture tube, insert the capillary tubes, sealed-end down, replace the stopper, and label the red-topped tube. Microtainer tubes have plastic plugs that fit over the top. They may be placed in a labeled tube or a labeled zipper-lock bag for transport. Always decontaminate collection containers before delivering them to the laboratory if blood was deposited on the surface during collection.

Handling the specimen after collection

The laboratory testing results are only as good as the specimen sent for testing. Specimens handled improperly after collection may provide incorrect results. They may even compromise the patient’s health. From the moment a specimen is collected, analytes in the blood begin to break down. By testing specimens as soon as possible, the laboratory tries to provide results that accurately represent the patient’s condition at the time of blood collection. After collection, blood may need to be processed before the sample is tested. This may include separation of plasma or serum from the red blood cells. If the venipuncture tube contains no anticoagulant (i.e., tubes with a red, a marbled red-gray, or a gold stopper), blood starts the clotting process when it touches the tube. The “clot” tubes should sit upright in a rack for 30 to 60 minutes at room temperature while a solid clot forms. Tubes with a clot accelerator should form a dense clot within 30 minutes. The presence of anticoagulants in the patient’s blood, such as warfarin (Coumadin) or heparin, may delay clotting. Once the clot has formed, every effort should be made to remove the clot from the serum within 2 hours.

Centrifugation

Removing the serum from a clot tube requires centrifugation. For thixotropic gel to form a barrier between the clot and the serum, certain requirements must be met. The tube must be centrifuged at a specified g-force , time, and temperature. A clinical centrifuge instruction manual should provide the appropriate settings for spinning blood specimens. The serum does not have to be removed from the tube after centrifugation because the gel has formed a barrier over the red blood cells. Once a tube with thixotropic gel has been centrifuged, it cannot be centrifuged again. The serum, however, can be decanted and centrifuged in another tube.

For tests that require plasma, the plasma should be removed from the cells as soon as possible. This can be done by centrifuging the tube and then aspirating the plasma off the cells. The plasma is then transferred to another tube using a disposable transfer pipet. You can also use a PST tube with a marbled green-gray top or a PST tube with a light green top. Both contain lithium heparin anticoagulant and a thixotropic gel, which form the necessary barrier when centrifuged.

Using reference laboratories

Certain blood tests, such as a CBC, require whole blood. It is wise to check the specimen requirements of the reference laboratory that will perform the test and follow the lab’s instructions for transport and storage. The College of American Pathologists (CAP) recommends that whole blood for automated blood counts be refrigerated and tested within 72 hours.

Often specimens must be transported by courier to other facilities. The Hazardous Materials Shipping Regulations, established by the Department of Transportation, apply to the packaging and shipping of hazardous materials by ground transportation. POLs that ship human specimens must be trained to properly handle, pack, and ship biohazard materials. Reference laboratories will frequently have couriers who pick up specimens. The specimens and their requisitions are typically placed in individual biohazard bags and sorted according to which reference lab is affiliated with the patient’s insurance.

Chain of custody

Blood samples may be collected as evidence in legal proceedings. Blood may be drawn for drug and alcohol testing, DNA analysis, or paternity testing. These samples must be handled according to special procedures to prevent tampering, misidentification, or interference with the test results.

Chain of custody is a legal term that refers to the ability to guarantee the identity and integrity of the specimen from the time of collection to the time test results are reported. It is a process used to maintain and document the history of a specimen. Documents should include the name or initials of the individual collecting the specimen, the name of each person who tests or transports the specimen, the date the specimen was collected or transferred, the name of the employer or agency, the specimen number, the patient’s or employee’s name, and a brief description of the specimen.

Collection kits are available that contain everything needed for the venipuncture, including the tube, the needle, the chain of custody forms and seals, the antiseptic, and even the tourniquet. Familiarize yourself with these kits before using them. Phlebotomists may be required to testify at legal proceedings if they are involved in the collection or testing of a legal sample.

Patient coaching

Phlebotomy can be a stressful event for some patients. Helping patients to remain calm and at ease is a high priority for the phlebotomist. Patients often express great concern when several tubes of blood must be drawn. It can seem like they are losing a lot of blood. You can put their fears to rest by explaining that the average adult has a little less than 5 L of blood (10 pints). Most adults can relate to donating a unit of blood, which is about 500 mL (1 pint). Because a large, red-topped tube contains 10 mL of blood, you would have to draw about 50 tubes to remove 500 mL of blood.

Provide as much explanation as needed to ease the patient’s anxiety. Often the patient can help by identifying the site of the last successful blood venipuncture. When appropriate, follow the patient’s suggestion in choosing the site for a venipuncture. When patients become active participants in the procedure, they remain more relaxed, talkative, and confident in your expertise as a phlebotomist.

Legal and ethical issues

Phlebotomy is an invasive procedure in which a sterile needle or lancet is inserted through the skin. Because the skin is penetrated, drawing blood becomes a surgical procedure and is subject to the laws and regulations of surgery. When a venipuncture is performed, the rules and regulations must be obeyed with no exceptions. Be sure to follow the written procedures in the laboratory. Become familiar with the regulations and standards established by CLSI and OSHA and by state and local agencies. Deviations from the standards leave the medical assistant open to malpractice. Document any situations in which the standard of care comes into question.

Patient-centered care

You may want to ask your patients how they would prefer to be addressed: By their first name? A nickname? Dr. Smith, Mr. Jones, Mrs. Blake, or Ms. Washington? Don’t assume that patients want to be called by their first name. Also, do not call patients “sweetie,” “honey,” or “dear.” Be respectful, professional, and patient focused.

Professional behaviors

Your appearance and actions reflect your laboratory or facility. A patient’s first impression of the facility often comes from the medical assistant. Clean fluid-impermeable laboratory coats and scrubs tell the patient the facility is clean; by sanitizing your hands in front of the patient and wearing gloves, you tell the patient you will treat him or her with care; and speaking knowledgeably provides the impression that the facility is staffed with professionals.

Medical assistants who perform venous and capillary blood collection must maintain a professional attitude yet remain sympathetic to the patient’s fears and anxiety about the procedure. Establishing an environment that encourages the person to relax can minimize the patient’s pain and discomfort during the procedure. Always remember to verify your patient’s identity and explain what you are going to do. Answer any questions the patient may have, and then make every effort to perform the procedure skillfully, quickly, and efficiently.

If your patient has a history of syncope when blood is drawn or if you suspect the patient may be very anxious during the procedure, have the person lie down. Assemble your equipment, and alert the provider before beginning the procedure. This type of professional care may help the patient get through the procedure without feeling anxious.