Pre-analytic Variables Flashcards
begins when a test is ordered and ends when testing begins
preanalytical or pre-examination phase
Factors during this testing phase when not properly adressed can lead to errors that can compromise specimen quality, jeopardize/harm the health and safety of the patient, and ultimately increase the cost of medical care
Preanalytical phase or pre-examination phase
What are the three purposes of performing tests? (ConDiMon)
- Confirm health or to screen for
- Diagnose
- Monitor disease
True or False. Test results need not to be compared with results expected of healthy individuals.
False. Tests results need to be compared with results from healthy individuals.
A range of values with high and low limits which are results used for comparison.
Reference range or reference interval
What happens when a specimen has been compromised and the results are not valid?
The physician could make a decision based upon incorrect information and thus jeopardize the patient’s care.
Refers to the resting metabolic state of the body early in the morning after fasting for approx. 12 hourrs.
Basal State
Ideal for establishing reference ranges on inpatients because the effects of diet, exercise, and other controllable factors on test results are minimied or eliminated.
Basal-state specimen
What variables influence basal state? (AADeDiDiu/CirDruEFGIJPPreSmoStreTemHum)
age, altitude, dehydration, diet, diurnal/circadian variations, drug therapy exercise, fever, gender, intramuscular injection, jaundice, position, pregnancy, smoking, stress, temperature and humidity
True or False. Outpatient specimens are not basal-state specimens and may have slightly different reference ranges (normal values).
True
True or False. RBC and WBC values are normally lower in newborns than in adults.
False. RBC and WBC are normally higher in newborns than in adults.
True or False. Kidney function decrease with age.
True
True or False.
S1: Decreased oxygen levels at higher altitudes cause the body to produce less RBCs.
S2: The higher the altitude, the greater the increase of RBCs
Only Statement 2 is correct. The higher the altitude, the more RBCs are produced.
A condition in which blood components that cannot easily leave the bloodstream become concentrated in the smaller plasma volume.
hemoconcentration
How long are patients asked to fast?
Approx. 8 to 12 hours
Fasting beyond 12 hours can cause serious health problems. What are examples of such?
- Electrolyte imbalance
2. Heart rhythm disturbances
Analytes that may be elevated in patients on high-protein diets (AUU)
Ammonia, urea, uric acid levels
Analytes that increase with the consumption of caffeine
Cortisol and adrenocorticotropic hormone (ACTH) levels
An analyte that increase with the ingestion of carbs or sugar-laden substances and insulin levels
Glucose (blood sugar) levels
An analyte that decrease and electrolyte balance can be altered by drinking excessive amounts of water and other fluids.
Hgb levels
An analyte that increase with ingestion of food such as butter, cheese, cream, and some enteral (tube feeding) preparations
lipid levels
Abnormally increased blood lipid content
Lipemia
The cloudy or turbid appearance of the specimen
Lipemic
How long can lipemia be present?
up to 12 hours
A condition characterized by increased bilirubin (a product of the breakdown of RBCs) in the blood, leading to deposits of yellow bile pigment in the skin, mucous membrane, and sclerae (whites of the eyes), giving the patient a yellow appearance
Jaundice/Icterus
Serum, plasma, or urine specimens that have an abnormal deep yellow to yellow-brown color due to high bilirubin levels
icteric
What does jaundice in a patient indicate?
Liver inflammation by hepatitis B or C virus
True or False.
S1: Avoid burned, scarred, or tattoed areas.
S2: Tattoed areas can have impaired circulation, may be more susceptible to infection, and contain dyes that can interfere with testing.
S3: The tattoed part may be an option for blood collection.
All statements are true.
These veins are effects of inflammation, disease, or chemotherapy drugs.
Sclerosed (hardened) or thrombosed (clotted) veins
Which statement is True?
S1: If the patient has damaged veins, draw above (proximal to) damaged veins
S2: if the patient has damaged veins, draw below (distal to) damaged veins
Statement 2 is correct.
Swelling caused by the abnormal accumulation of fluid in the tissues.
Edema
A swelling or mass of blood (often clotted) that can be caused by leaking from a blood vessel during or following venipuncture. A large bruise eventually spreads over the surrounding area.
Hematoma
Which statement is true?
S1: Never perform venipuncture through a hematoma unless there is no alternative site.
S2: Never perform a venipuncture through a hematoma.
Only S2 is true. If there is no alternative, veni must be performed distal to the hematoma site.
Refers to the the side where surgical breast removal procedure was performed
Mastectomy
Obstruction or stoppage of normal lymph flow due to lymph node removal
Lymphostasis
Tissue swelling due to impaired lymph flow
Lymphedema
A catheter placed in an artery.
Arterial line (a-line or art-line)
What does an arterial line catheter provide? Give 2.
- It provides accurate and continuous measurement of a patient’s blood pressure.
- It may be used to collect blood gas and other blood specimens for the administration of drugs such as dopamine.
The permanent surgical connection of an artery and vein. It is typically created to be used for dialysis.
Arteriovenous (AV) shunt, fistula, or graft
Connection of an artery and vein by direct fusion resulting in a bulging of vein
fistula
Connection of an artery and vein with a piece of vein or tubing that creates a loop under the skin.
Graft
A catheter or cannula connected to a stopcock or a cap with a diaphragm that provides access for administering medication or drawing blood.
Heparin or saline lock
A catheter inserted in a vein to administer fluids.
Intravenous (IV)
What happens when the patient has an IV in one arm?
Blood specimens should be collected from the other arm.
If a patient has IVs in both arms or the other arm is available, where should blood specimens be collected?
capillary puncture
How long should blood specimens shouldn’t be collected from a known previous IV site?
24 to 48 hours of the time the IV was discontinued
Consists of tubing inserted into a main vein or artery. It is used primarily for administering fluids and medications, monitoring pressures, and drawing blood. It is practical for patients who need IV access for an extendeed time and is especially beneficial for patients who do not have easily accessible veins.
Central vascular access device (CVAD) or indwelling line
Described as a loss of consciousness and postural tone resulting from insfufficient blood flow to the brain. It can last for as little as a few second or as long as half an hour.
Fainting/syncope
Sudden faintness or loss of consciousness due to a nervous system response to abrupt pain, stress, or trauma
vasovagal syncope
True or False. If a patient vomits during venipuncture, the procedure should still be continued when blood draw is currently in progress.
False. Even when draw is in progress, when a patient vomits, the procedure must be terminated immediately.
Tiny, nonraised red spots that appear on the patient’s skin wehn a tourniquet is applied.
Petechiae
An adjective used to describe an adverse condition brought on by the effects of treatment.
Iatrogenic
Refers to blood loss as a result of blood removed for testing
Iatrogenic blood loss
What happens when blood is removed on a regular basis or in large quantities?
Iatrogenic anemia
Blood loss to a point where life cannot be sustained.
Exsanguination.
Most often associated with deep or blind probing, especially in the area of the basilic vein, which is in close proximity to the brachial artery. It include a rapidly forming hematoma and blood filling the tube very quickly.
Inadvertent arterial puncture
Stagnation of the normal venous blood flow
Venous stasis
The trapping of blood in an extremity by compression of veins
Venostasis
Results when RBCs are damaged or destroyed and the hemoglobin they contain escapes in to the fluid portion of the specimen.
Hemolysis
Partially filled tubes
short draw
True or False. Short-draw serum tubes such as red tops and SSTs are generally acceptable for testing as long as the specimen is not hemolyzed and there is sufficient specimen to perform the test.
True
True or False. Underfilled anticoagulant tubes and most other additive tubes may not contain blood-to-additive ratio for short-draw.
True
True or False. Excess EDTA in underfilled additive tubes won’t shrink RBCs.
False. It may shrink RBCs, causing erroneously low blood cell counts and hematocrits and negatively affecting the morphological examination of the RBCs on a blood smear. It can aslo alter the staining characteristics of the cells on a blood smear.
True or False. Excess heparin in serum from underfilled green-top tubes may interfere with the testing of some chemistry analytes.
False. Excess heparin in plasma, not serum.
What results in excess sodium fluoride in underfilled gray-top tubes?
hemolysis of the specimen
What happens when coagulation tubes are underfilled?
they do not have the correct blood-to-additive ratio and will produce erroneous results
Tubes that are designed to contain smaller volume of blood where blood-to-additive ratio is is achieved during short draw
short-draw tubes
