Unit 6 - Pre-analytical Considerations in Phlebotomy Flashcards
The testing process begins for the laboratory when a test is ordered and ends when testing begins.
Preanalytical phase
Numerous factors associated with this phase of the testing process, if not properly addressed, it can lead to which of the following:
A. Errors that can compromise specimen quality.
B. Jeopardize the health and safety of the patient.
C. Ultimately increase the cost of medical care.
D. A and B only
E. All of the above
E.
A phlebotomist must have the technical skills needed to perform a blood draw, the ability to recognize __________ factors and address them, if applicable, to avoid or reduce any negative impact.
Preanalytical
T/F
Most tests are performed to confirm health or to screen for, diagnose, or monitor disease.
T
T/F
To be properly evaluated, test results typically need to be compared with results expected of healthy individuals.
T
T/F
Result values for most tests are established using specimens from normal, healthy individuals.
T
T/F
Results vary somewhat from person to person
T
Used for comparison become a range of values with high and low limits.
Reference RANGE or reference INTERVAL
Most reference ranges are for _____.
Healthy fasting individuals
Although less common, some tests have reference ranges for specific situations, such as patients who are ill or those being treated for certain disorders, such as __________.
Diabetes
T/F
One way a physician evaluates a patient’s test results is by comparing them to reference ranges and, if applicable, previous results on the same patient also.
T
T/F
If a specimen has been compromised and the results are not valid, a physician could make a decision based upon incorrect information and thus jeopardize the patient’s care.
T
__________ the resting metabolic state of the body early in the morning after fasting for approximately __ hours.
Basal; 12
Ideal for establishing reference ranges on inpatients because the effects of diet, exercise, and other controllable factors on test results are minimized or eliminated.
Basal-state specimen
Basal state is influenced by a number of physiologic patient variables such as __________, __________, and __________ that cannot be eliminated.
Age, gender, and conditions of the body
__________ specimens are not basal-state specimens and may have slightly different reference ranges.
Outpatient
T/F
Values for some blood components vary considerably depending upon the age of the patient.
T
Values that are normally higher in newborns than in adults.
RBC
WBC
Some physiological functions such as _____ function decrease with age.
Kidney or renal
A measure of kidney function that is directly related to the age of the patient, which must be factored in when test results are being calculated.
Creatinine clearance
T/F
Test results for some blood analytes show significant variation at higher elevations compared with results at sea level.
T
RBC count is elevated in _____ altitude.
Higher
T/F
Decreased oxygen levels at higher altitudes cause the body to produce more RBCs to meet the body’s oxygen requirements.
T
T/F
The higher the altitude, the greater the increase.
T
T/F
RBC counts and related determinations such as _____ and _____ have higher reference ranges at higher elevations.
Hgb
Hct
Other analytes that increase at higher elevations include __________ and __________.
C-reactive protein
Uric acid
Analytes that decrease in value at increased altitude include __________ (which in turn affects creatinine clearance tests) and __________.
Urinary creatinine
Plasma renin
Creatinine is _____ in higher altitude.
Decreased
Analytes generally take ______ to adapt to high elevations; however, they adapt to a return to sea level within days.
Weeks
Decrease in total body fluid.
Dehydration
Dehydration, which occurs, for example, with persistent vomiting or diarrhea, causes __________.
Hemoconcentration
Condition in which blood components that cannot easily leave the bloodstream become concentrated in the smaller plasma volume.
Hemoconcentration
Blood components affected by dehydration include __________, __________, __________, __________, __________, and __________.
RBCs
Enzymes
Ca (Calcium)
Fe (Iron)
Na (Sodium)
Coagulation factors
T/F
Results on specimens from dehydrated patients may not accurately reflect the patient’s normal status.
T
T/F
Results on specimens from dehydrated patients may not accurately reflect the patient’s normal status.
T
It is often difficult to obtain blood specimens from __________ patients.
Dehydrated
Calcium is __________ in dehydration.
Elevated
T/F
Blood analyte composition can be altered by the ingestion of food and drink.
T
T/F
Blood specimens collected soon after a meal or snack are unsuitable for many laboratory tests.
T
Diet effects on analytes are generally TEMPORARY and vary depending upon which of the following?
A. Amount and type of food or drink.
B. Length of time between ingestion and specimen collection.
C. A only
D. B only
E. Both A and B
E
Requiring a patient to _____ or follow a special diet eliminates most dietary influences on testing.
Fast
Patients are typically asked to fast approximately __________, depending on the test.
8 to 12 hours
Fasting is normally done overnight __________ the last evening meal, with specimens collected the following morning __________ the patient has eaten.
After; before
Fasting beyond 12 hours can cause serious health problems, such as __________.
Electrolyte imbalance and heart rhythm disturbances.
T/F
Fasting specimens, especially those requiring a 12-hour fast, should be collected promptly without unreasonable delay.
T
T/F
Patients are allowed to drink water during fasting unless they are NPO (nothing by mouth) for another procedure.
T
Refraining from drinking water while fasting can result in __________, which can negatively affect test results and also make blood collection more difficult.
Dehydration
__________, __________, and __________ may be elevated in patients on high-protein diets.
Ammonia
Urea
Uric acid
__________ and __________ levels have been shown to increase with the consumption of beverages containing CAFFEINE
Adrenocorticotropic hormone (ACTH)
Cortisol
__________ increase dramatically with the ingestion of carbohydrates or sugar-laden substances but return to normal within 2 hours if the patient has normal glucose metabolism.
Glucose
Eating carbohydrates can also increase __________ levels.
Insulin
_____ levels can decrease and electrolyte balance can be altered by drinking __________ amounts of water and other fluids.
Hgb
Excessive
Increase with ingestion of foods such as butter or margarine, cheese, cream, and some enteral (tube feeding) preparations.
Lipid levels
Tube feeding
Enteral preparations
Lipid is a term meaning __________.
Fat-soluble
Abnormally increased blood lipid content.
Lipemia
T/F
Lipids do not dissolve in water and thus high levels of lipids are visible in serum or plasma.
T
Lipids appear milky or turbid, and the specimen is described as being __________.
Lipemic
Lipemia can be present for up to __ hours.
12
Accurate testing of triglycerides (a type of lipid) requires a __-hour fast.
12
T/F
Some chemistry tests cannot be performed on lipemic specimens because the cloudiness interferes with the testing procedure.
T
T/F
Lipemia in a fasting specimen is rare.
T
T/F
A test requires a fasting specimen but the serum or plasma sample submitted is lipemic, it is a clue that the patient may not have been fasting.
T
T/F
Some test methods that detect occult (hidden) blood in stool specimens also detect similar substances in meat and certain vegetables.
T
T/F
A special diet that eliminates these foods must be followed for several days before the specimen is collected.
T
Triglycerides, certain liver enzymes, and other liver function analytes are increased by chronic consumption or recent ingestion of large amounts of alcohol, which can also cause __________.
Hypoglycemia
Also affect the composition of blood analytes.
Malnutrition and starvation
Long-term starvation __________ cholesterol, triglycerides, and urea levels and __________ creatinine, ketone, and uric acid levels.
Decreases; increases
The levels of many blood components normally exhibit __________ (happening daily) or __________ (having a 24-hour cycle) variations or fluctuations.
Diurnal; circadian
Factors that play a role in diurnal variations.
Posture
Activity
Eating
Daylight
Darkness
Being awake or asleep
Melatonin levels are affected by _____.
Light
Melatonin levels __________ at night when it is dark.
Increase
Melatonin levels __________ during daylight hours.
Decrease
Maximum __________ and __________ levels normally occur in the predawn hours of the morning during sleep.
Renin
TSH
Peak __________ levels normally occur later in the morning around 8:00 AM.
Cortisol
Other blood components that exhibit diurnal variation with highest levels occurring in the morning.
Aldosterone
Bilirubin
Cortisol
Hgb
Insulin
Iron
Potassium
Testosterone
RBCs
Blood levels that are normally lowest in the morning.
Eosinophils
Creatinine
Glucose
Growth hormone
Triglycerides
Phosphate
T/F
Diurnal variations can be large.
T
For example the levels of _____, _____, and _____ can differ by 50% or more between morning and late afternoon.
Cortisol
TSH
Iron
T/F
A change of several time zones can affect diurnal rhythm and the tests associated with it.
T
T/F
Only a day may be required to restore a normal rhythm.
F
Tests influenced by diurnal variation are often ordered as _____ tests.
Timed
T/F
It is important to collect them as close to the time ordered as possible.
T
T/F
Some drugs alter physiological functions, causing changes in the concentrations of certain blood analytes.
T
T/F
In drug therapy, the effect may be desired or an unwanted side effect or sensitivity.
T
T/F
It is common for physicians to monitor levels of specific blood analytes while a patient is receiving drug therapy.
T
__________ drugs can cause a decrease in blood cells, especially _____ and _____.
Chemotherapy
WBCs
Platelets
Many drugs are toxic to the liver, as evidenced by increased levels of liver enzymes such as ___.
Aminotransaminase (AST)
Alkaline phosphatase (ALP)
Lactate dehydrogenase (LDH)
AST is also called as _____?
Serum glutamic-oxaloacetic transaminase (SGOT)
Drug therapy creases production of __________.
Clotting factors
Opiates such as morphine __________ levels of liver and pancreatic enzymes.
Increase
Oral contraceptives can ELEVATE the _____ and DECREASE levels of vitamin ___.
Erythrocyte sedimentation rate (ESR)
B12
Steroids and diuretics can cause pancreatitis and an increase in _____ and _____ values.
Amylase
Lipase
Thiazide diuretics can elevate __________ and __________ levels and decrease __________ and __________ levels.
Calcium and glucose
Sodium and potassium
T/F
Drugs can also interfere with the actual test procedure, causing false increases or decreases in test results.
T
T/F
A drug may compete with the test reagents for the substance being tested, causing a falsely low or false-negative result, or the drug may enhance the reaction, causing a falsely high or false-positive result.
T
An acronym for substances that interfere in the testing process is CRUD, which stands for?
Compounds Reacting Unfortunately as Desired
T/F
It is ultimately up to the physician to prevent or recognize and eliminate drug interferences, this can be a complicated issue that requires cooperation between the physician, pharmacy, and laboratory to make certain that test results are not affected by medications.
T
T/F
Phlebotomists can play a role in drug therapy complications by noting on the requisition when they observe medication being administered just prior to blood collection.
T
According to CAP guidelines, drugs that interfere with blood tests should be stopped or avoided __________ hours prior to obtaining the blood sample for testing.
4 to 24 hours
Drugs that interfere with urine tests should be avoided for __________ hours prior to the urine sample collection.
48 to 72
Reduced by exercise.
Arterial pH
PaCO2
Elevated by moderate muscular activity
Glucose & insulin
Total protein
Lactic acid
Creatinine
__________ is released from the cells during exercise, increasing levels in the plasma.
Potassium (K+)
T/F
Levels generally return to normal after several minutes of rest.
T
T/F
The simple exercise of pumping the hand (i.e., making and releasing a fist) during venipuncture is enough to erroneously increase potassium levels.
T
Increased by exercise.
Skeletal muscle enzymes
Increased by exercise.
Skeletal muscle enzymes
Skeletal muscle enzyme levels are increased by exercise, with levels of __________ and __________ remaining elevated for 24 hours or more.
Creatine kinase (CK)
Lactate dehydrogenase (LDH)
T/F
Athletes generally have higher resting levels of skeletal muscle enzymes, and exercise produces less of an increase.
T
Vigorous exercise shortly before blood collection can temporarily increase __________ levels by 6% or more.
Cholesterol
T/F
Levels can remain elevated for up to an hour after the exercise has stopped.
T
Vigorous or sustained exercise can also affect __________.
Hemostasis
T/F
There is an increased number of platelet clumps were seen in a study of runners evaluated immediately after running the Boston marathon.
T
Fever affects the levels of a number of _____.
Hormones
Fever-induced hypoglycemia increases _____ levels, followed by a rise in _____ levels.
Insulin
Glucagon
Fever also increases _____ and may disrupt its normal diurnal variation.
Cortisol
T/F
A patient’s gender affects the concentration of a number of blood components.
T
T/F
RBC, Hgb, and Hct normal values are higher for males than for females.
T
A recent intramuscular injection can increase levels of _____ and the skeletal muscle fraction of LDH.
Creatine kinase (CK)
T/F
It is recommended that CK and LDH levels be drawn before intramuscular injection or at least 1 hour after injection.
T
T/F
Muscular trauma from injuries or surgery can also increase CK levels.
T
Other term for jaundice.
Icterus
A condition characterized by increased bilirubin in the blood, leading to deposits of yellow bile pigment in the skin, mucous membranes, and sclerae, giving a patient a yellow appearance.
Jaundice or icterus
It is increased in the blood that leads to jaundice.
Bilirubin
This means relating to or marked by jaundice and is used to describe serum, plasma, or urine specimens that have an abnormal deep yellow to yellow-brown color due to high bilirubin levels.
Icteric
T/F
The abnormal color can interfere with chemistry tests based on color reactions, including reagent-strip analyses on urine.
T
Jaundice in a patient may indicate liver inflammation caused by _____.
Hepatitis B or C virus
T/F
Body position before and during blood collection can influence specimen composition.
T
Going from supine to an upright sitting or standing position causes blood fluids to filter into the tissues, decreasing _____ volume in an adult up to 10%.
Plasma
Only _____ fluids can pass through the capillaries.
Protein-free
What are the blood concentration of components that are protein in nature or bound to protein that increases.
Aldosterone
Bilirubin
Blood cells
Calcium
Cholesterol
Iron
Protein
Renin
T/F
In most cases the concentration of freely diffusible blood components is not affected by postural changes.
T
T/F
A significant increase in potassium (K+) levels occurs within 30 minutes of standing; this has been attributed to the release of intracellular potassium from muscle.
T
T/F
A change in position from lying to standing can cause up to a 15% variation in total and high-density lipoprotein (HDL) cholesterol results.
T
T/F
The National Cholesterol Education Program recommends that lipid profiles be collected in a consistent manner after the patient has been either lying down or sitting quietly for a minimum of 5 minutes.
T
_____ and _____ change more slowly but can double within an hour.
Plasma aldosterone
Renin
Patients are required to be _____ (lying down) for at least 30 minutes prior to aldosterone specimen collection.
Recumbent
T/F
Plasma renin-activity levels require documentation of the patient’s position during collection.
T
T/F
The RBC count on a patient who has been standing for approximately 15 minutes will be higher than a basal-state RBC count on that patient.
T
T/F
Calling outpatients into the drawing area and having them sit in the drawing chair while paperwork related to the draw is readied can help minimize effects of postural changes on some analytes.
T
T/F
Pregnancy causes physiologic changes in many body systems.
T
T/F
Results of a number of laboratory tests must be compared with reference ranges established for pregnant populations.
T
T/F
Increase in body fluid is normal during pregnancy.
T
T/F
Increase in body fluid during pregnancy have a diluting effect on the RBCs, leading to lower RBC counts.
T
T/F
A number of blood components are affected by smoking. The extent of these effects depends upon the number of cigarettes smoked.
T
Increases when the patient smoke prior to specimen collection.
Cholesterol
Cortisol
Glucose
Growth hormone
Triglycerides
WBC counts
Chronic smoking often leads to decreased pulmonary function and increased _____ and _____.
RBC counts
Hgb levels
Smoking can also affect the body’s immune response, typically lowering the concentrations of immunoglobulins ___, ___, and ___ but increasing levels of ___.
IgA, IgG, IgM
IgE
T/F
Skin-puncture specimens may be difficult to obtain from smokers because of impaired circulation in the fingertips.
T
Emotional stress such as anxiety, fear, or trauma can cause transient (short-lived) elevations in _____.
WBCs
T/F
Studies of crying infants have demonstrated marked increases in WBC counts, which returned to normal within 1 hour after the crying stopped.
T
T/F
Consequently CBC or WBC specimens on an infant are ideally obtained after the infant has been sleeping or resting quietly for at least 30 minutes.
T
T/F
If they are collected while an infant is crying, this should be noted on the report.
T
