CC (LAB) Flashcards
3 Major Phases of Testing
Pre-Analytic Phase
Analytic Phase
Post-Analytic Phase
occurs first in the laboratory process
involves steps such as the actual ordering of the tests by physicians, as well as sample collection
Pre-Analytic Phase
This phase includes what is usually considered the “actual” laboratory testing or the diagnostic procedures, processes, and products that ultimately provide results.
Analytic Phase (Chemical Analyses)
final phase of the laboratory process.
This phase culminates in the production of a final value or result
Post-analytic Phase (Data Management)
is the act of obtaining a blood sample from a vein using a needle attached to a collection device or a stoppered evacuated tube
Phlebotomy or Venipuncture
Comes from the Greek words “ Phleb”, which means ____, and “tomia”, which means ____
vein, cutting
The most frequent site for venipuncture is the ____ (located in the anterior elbow at fold)
antecubital fossa
have thick walls to withstand the pressure of ventricular contraction, which creates a pulse that can be felt, distinguishing them from veins.
Arteries
THE VASCULAR SYSTEM
veins, arteries, capillaries
When arterial blood is collected by syringe, the pressure normally causes blood to “pump” or pulse into the syringe under its own power.
Arteries
Normal systemic arterial blood is bright red because it is oxygen rich.
Arteries
have thinner walls than the same-size arteries because blood in them is under less pressure.
veins
They collapse more easily.
veins
Blood is kept moving through veins by _____ and the opening and closing of valves that line their inner walls.
skeletal muscle movement
Normal systemic venous blood is dark bluish red because it is oxygen poor.
veins
are only one cell thick to allow the exchange of gases and other substances between the tissues and the blood.
capillaries
The capillary bed in the skin can easily be punctured with a lancet to provide blood specimens for testing
capillaries
3 Main Veins in the Antecubital Fossa
median cubital vein
cephalic vein
basilic vein
located near the center of the antecubital fossa.
It is the preferred vein for venipuncture in the H pattern because it is typically large, closer to the surface, and the most stationary, making it the easiest and least painful to puncture and the least likely to bruise.
median cubital vein
located in the lateral aspect of the antecubital fossa.
It is the second-choice vein in the H pattern. Although often harder to palpate (feel) than the median cubital, it is fairly well anchored and often the only vein that can be felt in obese patients.
Cephalic vein
located on the medial side of the antecubital fossa.
Basilic vein
It is the last choice in either pattern.
Although normally large and easy to feel, it is not well anchored and rolls easily, increasing risk of puncturing a median cutaneous nerve branch or the brachial artery that is nearby.
Basilic vein
CLSI recommends against using it unless no other vein in either arm is more prominent
Basilic vein
- is normally uniform throughout the body.
- it is primarily reserved for blood gas evaluation and certain emergency situations and performed only by those with special training.
Arterial blood composition
is affected by metabolic activity of the tissue it drains and varies by collection site.
-It differs most from arterial blood in its lower oxygen content, but chloride, glucose, pH, CO2, lactic acid, and ammonia levels may also differ.
Venous blood composition-
contains arterial and venous blood plus tissue fluid.
Capillary blood-
Because it enters capillaries under pressure, the arterial portion is highest. Warming the site increases it further.
Capillary blood-
Blood is approximately
55% fluid and 45% blood cells
is normally a clear, pale yellow fluid (nonfasting serum can be cloudy due to lipids) separated from clotted blood by centrifugation.
Serum-
- is normally a clear to slightly hazy, pale yellow fluid that separates from the cells when blood in an anticoagulant tube is centrifuged.
Plasma
Stat and other tests requiring a fast turnaround time (TAT) are often collected in tubes containing ____ because they can be centrifuged immediately to obtain plasma.
heparin anticoagulant
contains both cells and plasma
Whole blood -
It must be collected in an anticoagulant tube to keep it from clotting.
Whole blood -
is used for most hematology tests and many point-of-care tests (POCTs), especially in acute care and stat situations
It must be collected in an anticoagulant tube to keep it from clotting.
is the preferred method because blood is collected directly from the vein into a tube, minimizing the risk of specimen contamination and exposure to the blood.
. Evacuated tube system (ETS)
used on small, fragile, or damaged veins
Syringe Method -
set can be used with the ETS or a syringe and is often used to draw blood from infants and children, from hand veins, and in other difficult-draw situations.
Winged infusion set (butterfly) -
- prevent blood from clotting and include ethylenediaminetetraacetic acid (EDTA), citrates, heparin, and oxalates. Each is designed for use in certain types of testing, and it is important to use the correct one.
Anticoagulants
prevent glycolysis, which can decrease glucose concentration by up to 10 mg/dL per hour.
Antiglycolytic agents -
The most common antiglycolytic agent, ____, preserves glucose for up to 3 days and inhibits bacterial growth.
sodium fluoride
is used to collect ethanol specimens to prevent an increase in alcohol due to fermentation by bacteria
sodium fluoride
are coagulation factors such as thrombin and substances such as glass (silica) particles and inert clays like diatomite (Celite) that enhance clotting by providing more surface for platelet activation.
Clot activators -
are inert substances contained in or near the bottom of certain tubes.
Thixotropic gel separators -
is made of pliable non-latex rubber flat band or tubing
It is wrapped around the arm, causing cessation of blood flow and dilation of the veins, making for easier detection.
Tourniquet
The gauge of the needle is inversely related to the size of the needle; the larger the number, the smaller the needle bore and length. Routine venipuncture uses a
23- or 21-gauge needle
: scar buildup that can result from many venipunctures in the same area for an extended period, improper redirection of the needle, or probing and can impair vein patency and make it difficult to perform subsequent venipunctures.
Vein damage
: backflow of blood from the tube into the patient’s vein that can occur if blood in the tube is in contact with the needle during a blood draw. To prevent reflux, the patient’s arm must be in a downward position so that the collection tube fills from the bottom up.
Reflux
results from poor site selection, inserting the needle too deeply or quickly, patient movement on needle insertion, excessive or lateral needle redirection or blind probing. Extreme pain, a burning or electric shock sensation, arm numbness, or pain radiating up or down the arm are all signs of nerve involvement that require immediate removal of the needle.
Nerve injury:
rapid swelling at or near the venipuncture site due to blood leaking into the tissues
Hematoma formation:
anemia as a result of treatment (e.g., frequent blood draws or removing large quantities at a time). Only minimum amounts of blood should be drawn from infants.
Iatrogenic anemia:
: accidentally sticking an artery; often the result of deep or blind probing or attempting to draw from the basilic vein. Venipuncture must be discontinued and pressure applied for 5 minutes. Identify specimen as arterial blood if submitted for testing.
■ Inadvertent arterial puncture
adverse effects of bacterial multiplication. Infection risk can be minimized by using aseptic technique, including cleaning the site properly and not touching it again before needle insertion.
Infection of the site:
