Phlebotomy: Collecting and Processing Patient Blood Specimens

quality assessment

used to describe the management of the treatment of the whole patient

quality assessment

preparation of a patient for any specimens to be collected

collection of valid samples

proper specimen transport

performance of the requested lab analyses

validation of test results

recording and reporting the assay results

transmitting test results to the patient’s medical record

documentation, maintenance, and availability of records describing quality assessment practices and quality control measures

1. specimen collection tube is not filled

2. patient identification error

3. inappropriate specimen collection tube or container

4. test request error

leading causes of preanalytical errors in venipuncture

other types of preanalytical errors

hemolyzed specimens

blood clots caused by inadequate mixing of evacuated collection tubes containing anticoagulant

other factors that affect the volume of blood collected in an evacuated tube

quality of specimen

depends on how a specimen was collected, transported, and processed

before phlebotomy preanalytical error

misidentified patient

wrong evacuated specimen tubes

inadequate fasting conditions

not coordinated with medication

during phlebotomy preanalytical errors

excess tourniquet time

incorrect order of draw of specimen

failure to gently invert specimen collection tubes several times, if the tube contains an anticoagulant or additive

under filling evacuated tubes

after phlebotomy preanalytical errors

improper transport or storage conditions

hemolysis caused by improper mixing of blood with the additive (shaking)

incorrect specimen-handling directions (such as improper centrifugation or clot contact time)

patient care partnership

the delivery of health care that involves a partnership between patients and physicians and other health care professionals

American Hospital Association

association that developed the patient care partnership document

Patient Care Partnership

document that stresses:

• high-quality hospital care

• clean and safe environment

• involvement by patients in their care

• protection of patient’s privacy

• help for patients when leaving the hospital

• help for patients with billing claims

replaces the former Patient’s Bill of rights

written by the American Hospital Association

pediatric patients

important to be gentle and compassionate

acknowledge both patient and parent

do not hurry

bolster their morale

adolescent patients

be relaxed and alert to possible anxiety

allow enough time for procedure

establish eye contact

allow patient to maintain sense of control

Adult patients

tell them briefly what to expect and what test involves

greet friendly and in a tactful manner

pleasant conversation can be started

tell them about purpose of the blood collection

geriatric patients

treat with dignity and respect

do not demean them

address patient with a more formal title

may enjoy short conversation

keep flexible agenda

speak slightly slower and louder if patient is hard of hearing

phlebotomy challenges

can include:

simply finding/identifying a patient

sleeping/unconscious patient

patients who are apprehensive to phlebotomy

combative patients due to alcohol ingestion, drug use, or psychiatric condition

mentally challenged patients

minors

infection control

the chain of infection requires a continuous link of 3 factors:

1. reservoir

2. means of transmission

3. susceptible host

(also portal of exit for an infectious agent and a portal of entry into the host)

reservoir

an infected symptomatic or nonsymptomatic host

means of transmission

a contaminated object, food, or water

susceptible host

a patient, a health care worker, or a visitor

isolation as a safety system

understood as the separation of a seriously ill patient to stop the spread of infection to others or to protect the patient from irritating

isolation

changed as a special set of precautions performed by a few health care providers for a select few patients to a safety system that is practiced by everyone in the course of routine patient care

modern isolation techniques

incorporate a broad-based theory that addresses the needs of both patients and employees to ensure that the safest possible environment is maintained throughout the health care facility

standard and additional precautions

a two-tiered system that minimizes the risk for infection and maximizes the safety level within the health care facility’s environment

standard precautions

recognizes the need to reduce the risk for microbial transmission, including HIV, from both identified and unidentified sources of infection

require that protective protocols be followed whenever contact is made with blood and body fluids

first tier of infection control

addition precautions

controls the transmission of infectious agents under special circumstances when standard precautions alone may not be enough

transmission-based precautions include:

• contact precautions

• droplet precautions

• airborne precautions

contact precautions

designed to stop the spread of microorganisms through direct contact (skin-to-skin contact) and indirect contact (person making contact with a contaminated inanimate object)

includes:

• wearing gloves when making contact with the patient’s skin or with inanimate objects that have been in direct contact with the patient

• use of gowns when clothing is likely to come in contact with the patient or items in the patient’s room

droplet precautions

protect health care workers, visitors, and other patients from droplets that may be expelled during coughing, sneezing, or talking

guidelines include:

• using a mask when working close to the patient

• patient placement guidelines

• special guidelines for transport/placement of patients

• environmental management of equipment

particularly important when influenza or whooping cough is present

airborne precautions

designed to provide protection from airborne bacteria or dust particles that may be suspended in the air for an extended period of time

guidelines include:

• the use of respiratory protection

• the use of special air-handling systems to control airborne bacteria

must be observed when patients have measles or tuberculosis

blood

type of specimen most frequently analyzed in the clinical lab

phlebotomist

critically important member of the lab team

represents the lab to patients —> lab ambassadors

needs to project a professional image

must demonstrate professionalism by their conduct, appearance, composure, and communication skills

expected to deliver unexcelled customer satisfaction

blood sample collection

analysis process

one area of improvement in lab test results in ….

before testing

preanalytical errors

the majority of lab errors are caused by mistakes ________ or ___________

professional training

errors in the preanalytical phase involving phlebotomists can be reduced through appropriate ___________ and constant vigilance in testing

postprandial specimen

blood collected directly after a meal

2 hours

when testing blood glucose, a sample may be collected _______ postprandially

after this, levels return back to fasting level

blood collection variables

food intake

medication

activity

time of day

timed drawing of specimen

peak and trough drug levels

post medication conditions

posture (whether the patient is lying in bed or standing)

immobilization (resulting from prolonged bed rest)

circadian/diurnal variations (cyclical variations throughout the day)

recent food ingestion (ex. caffeine intake)

smoking (nicotine effect)

alcohol ingestion

blood collection procedures

general sources: venous blood and peripheral (capillary) blood

arterial blood may be needed to perform specific procedures such as blood gas analysis

venous and peripheral (capillary) blood

two general sources of blood

Clinical and Lab Standards Institute (CLSI)

set standards for the collection of venous blood (venipuncture or phlebotomy) and capillary blood (finger prick or skin puncture)

serum

pale-yellow fluid that separates from the clot and appears in the upper portion of the tube

fibrinogen

substance found in circulating blood (in plasma portion) that is necessary for coagulation to occur

its converted to fibrin when clotting occurs which lends the structure to the clot in the form of fine threads in which the RBCs and the WBCs are embedded

anticoagulant

substance that is mixed with blood to prevent blood from clotting

plasma

when blood is mixed with an anticoagulant, the blood can be separated into _______ and cellular components (erythrocytes, leukocytes, and platelets

plasma

straw-colored fluid formed with anticoagulant is present

plasma

top layer

consists of water and solutes

a liquid that normally represents about 55% of the total blood volume

buffy coat

a grayish-white cellular middle layer composed of WBCs and platelets

normally about 1% of the total blood volume

erythrocytes

bottom layer

consisting of packed RBCs

normally about 45% of total blood volume

environmental factors associated with evacuated blood collection tubes

ambient temp

altitude

humidity

sunlight

ambient temp

tube is stored at low temp —> pressure of gas inside decreases —> increase in draw volume

tube is stored at high temp —> reductions in draw volume

increased temps can also have a negative effect on the stability of certain tube additives (gels can degrade when exposed to high temps)

altitude

when blood is drawn at high altitudes —> pressure of gas in tube is decreased —> draw volume is lower

humidity

conditions of extremely high humidity —> migration of water vapor inside of tube —> draw volume increases

conditions of extremely low humidity —> water vapor escapes from the tube —> draw volume decreases

light

special additive that can be added to CTAG tube is sensitive to light

exposed to light —> inaccurate results

EDTA

anticoagulant used for complete blood cell count (CBC), hemoglobin, packed cell volume, total leukocyte count, leukocyte differential count, and platelet count

routine anticoagulant in blood banking

removes ionized calcium —> forms an insoluble calcium salt that prevents coagulation

sodium citrate

anticoagulant used for APTT and PT testing + classic Westergren ESR

heparin

anticoagulant used as an in vitro and in vivo anticoagulant

only coagulant used for the determination of pH, blood gases, electrolytes and ionized calcium

acts as an antithrombin (substance that inactivates the blood-clotting factor thrombin and factor Xa) —> inactivation of thrombin is caused by the complexing of heparin with the antithrombin III molecule, catalyzing the inhibition of thrombin

sodium fluoride

used a dry additive and a weak anticoagulant

used primarily to preserve blood glucose specimens by preventing glycolysis or destruction of glucose

adverse effects of additives

caused by using an improper additive or of using the wrong amount of additive:

• interference with the assay

• removal of constituents

• effect on enzyme action

• alteration of cellular constituents

• incorrect amount of anticoagulant

interference with the assay

additive may contain a substance that is the same, or reacts in the same way, as the substance being measured

ex. use of sodium oxalate

removal of constituents

the additive may remove the constituent to be measured

effect on enzyme action

additive may affect enzyme reactions

alteration of cellular constituents

additive alters cellular constituents —> altering appear and data

incorrect amount of anticoagulant

if too little additive is used —> partial clotting of whole blood will occur —> interferes with cell counts

if too much anticoagulant is added —> dilutes blood sample —> interferes with certain quantitative measurements

color of the tube top

the presence or absence of additives in evacuated tubes is indicated by the __________

40 - 77 degrees F

storage temperature for blood collection tubes should be between ________

yellow tube

use: blood cultures —> SPS aerobic and anaerobic

additive: culture media

drawn first

light blue tube

use: coagulation studies

additive: sodium citrate

invert 3-4 times

red tube

use: chemistry

additive: serum tube (plastic or glass)

invert 5 times

gold/red tube

use: chemistry

additive: gel separator clot activator

invert 5 times

orange tube

use: chemistry

additive: BD vacutainer RST

green tube

use: chemistry

additive: heparin

invert 5 times

purple tube

use: hematology, hemoglobin, ATC

additive: K2 EDTA

intvert 8-10 times

pink tube

use: blood group cross matching

additive: EDTA

invert 8 times

gray tube

use: blood glucose

additive: potassium oxalate, sodium fluoride

invert 8-10 times

yellow —> light blue —> red/gold —> orange —> green —> purple/lavender —> pink/white —> gray

order of draw

gray tube

color used for fasting blood sugar, lactic acid, and alcohol level assays

lavender tube

color used for CBC, sedimentation rate, routine immunohematology testing —> ABO blood grouping

light blue tube

color used for coagulation assays

pink tube

color used for blood bank testing with a label and closure that meet the American Association of Blood Banks standards

red tube

color used for testing in blood bank, chemistry, and serology

tan tube

color used for blood lead level assay

yellow tube

color used for blood culture collection

syringe technique

used for special cases of venous blood collection

if a patient has particularly difficult veins, or if other special circumstances exist, this technique may be used

general protocol

1. pleasantly introduce yourself

2. identify the patient

3. check test requisitions

4. label specimen tubes after collecting blood

supplies for venous blood collection

test requisition

tourniquet and disposable gloves

sterile disposable needles and needle holder

various evacuated blood tubes

alcohol (70%) and gauze square or alcohol wipes

any special equipment

adhesive plastic strips

special site selection situations

intravenous lines

edema

scarring or burn patients

dialysis patients

mastectomy patients

intravenous lines

a limb with an IV line running should not be used for venipuncture because of contamination to the specimen

the patietn’s other arm or an alternate site should be selected

edema

abnormal accumulation of fluid in the intracellular spaces of tissue

harder to take venous blood collection in these patients

scarring/burn patients

veins are very difficult to palpate in areas with extensive scarring or burns

alternate sites or capillary blood collection should be used

dialysis patients

blood should never be drawn from a vein in an arm with a cannula (temporary dialysis access device) or fistula (permanent surgical fusion of vein and artery)

trained staff member can draw blood from a cannula

preferred venipuncture site is a hand vein or a vein away from the fistula on the underside of the arm

mastectomy patients

patient has had lymph nodes removed adjacent to the breast, venipuncture should not be performed on the same side as the mastectomy

phlebotomy problems

1. refusal by the patient to have blood drawn

2. difficulty in obtaining a specimen

3. movement of the vein

4. sudden movement by the patient or phlebotomist that causes the needle to come out of the arm prematurely

5. improper anticoagulant

6. inadequate amount of blood in an evacuated tube

7. fainting or illness after venipuncture

phlebotomy complications

1. vascular complications —> bleeding from site and hematoma formation

2. infections

3. loss of consciousness or nausea and vomiting

4. anemia

5. neurological complications

6. cardiovascular complications

7. dermatologic complications

fingerprick POCT

ideal for limited-resource countries because of factors that include its simplicity and the low cost of supplies

offers diabetic patients the benefit of in-home testing for glucose

because of small sample size, it presents some complications:

• accepting the inaccuracy of finger prick blood asa trade-off for easy blood collection

• collecting, reading, and averaging multiple drops to improve accuracy even if this requires more cost and time

• if high accuracy is required, collecting and analyzing venous blood instead of capillary blood

blood spot collection for neonatal screening programs

specimen is collected on filter paper and sent to the approved testing lab for analysis

collection is usually done by heel puncture

tests newborns for certain diseases that can result in serious abnormalities

capillary blood for testing at the bedside (point-of-care testing)

quantitative determinations for glucose are made available within 1-2 minutes

many diabetic outpatients perform this at home

procedural errors that lead to failure to draw blood

tube positive and vacuum

collapsed vein

needle position

capillary blood collection supplies

alcohol (70%) and gauze squares or alcohol wipes

disposable gloves and sterile small gauze squares

sterile disposable blood lancets

blood gases —> ethylenediaminetetraacetate tubes —> other additive minicontainers —> serum

order of draw for capillary specimen

24 hours

in general, specimens should be analyzed within ____ of collection