pre-analytical considerations Flashcards
Testing process begins when a test is ordered and ends when testing begins.
Preanalytical (before analysis) or
pre-examination phase
*The doctors ordered the tests.
Skills required for a phlebotomist
★ Technic, skills to perform blood draw
★ Ability to recognize pre examination factors and address them. (did not fast as required, if patient is dehydrated, labeled correctly)
Shows the high and low limits of results values compared to healthy individuals.
reference range/ interval
- often called normal values
- most often based on healthy fasting individuals
how can a physician evaluates a patients test result
by comparing them with references range and if available, the patient’s previous results
- if a specimen has been compromised and the results are not valid, a physician could make diagnosis or decision based on incorrect information and thus jeopardize the patients care
Refers to the resting metabolic state of the body early in the morning after fasting for approximately 12 hours.
basal state
Min. 8 hours to max. 12 hours only.
beyond12 hours:
hypoglycemia (blood sugar (glucose) level drops too low.
electrolyte imbalance
heart rhythm disturbances
basal state specimen is ideal for establishing what
reference ranges on inpatients
it needs to be basal state specimen as it may effect on diet, exercise
basal state is influenced by
age
gender
body conditions (on that present time)
fasting vs NPO
fasting:
no intake of food pero pwede
plain water, 1 glass only
nothing per orem: (stricter than fasting)
nothing by mouth, avoid food and drink
briefly explain the physiological variables in age
rbc and wbc normally higher in newborn and children
creatine clearance
- measures how well your kidneys are working
- waste product from muscle metabolism excreted through the kidneys
- as we age, kidney function decreases (means might not filter creatinine) and reduce muscle mass (means less creatinine produced)
creatine vs creatinine
creatine:
- active firm used in the body
- provide quick energy for muscle contractions (obtained from food and supplement)
↑ good for muscle
↓ concerning
creatinine:
- “waste” form of creatine
- filtered out of your blood by your kidneys
↑ kidney issue
↓misleading
briefly explain the physiological variables in altitude that is increasing
↑ rbc to compensate O2
hence it will ↑ hemoglobin & hematocrit (% of RBC in blood)
↑ C-reactive protein
- produced by the liver in response to inflammation
- its like a warning signal that smthing is unusual and need to react
↑ uric acid
- waste products from breakdown of food and tissues
- acts as an antioxidant and has to work harder cos of decreasing O2
briefly explain the physiological variables in altitude that is decreasing
↓ urine
- to conserve H20 in drier high-altitude air
- maintain proper blood volume
↓ creatinine
↓ renin
- an enzyme that regulate fluid volume in the body
*adaptation: our body can adapt to changes in an environment but it takes time
briefly explain the physiological variables in dehydration
↓ total body fluid (diarrhea, persistent vomiting) which leads to hemoconcentration
↑ rbc, enzymes, Fe, Ca, Na+, K+, coagulation factors
- this means that you lose water, these substances remains the same but dissolved in less fluid
hemoconcentration
cannot easily leave the bloodstream
bcm concentrated in the smaller plasma vol
true or false:
it is often difficult to obtain blood specimen from dehydrated patients
true
an examplein altitude
tired of walking up a mountain, difficult in breathing = hypoxia
deprive of O2 hence it will produce O2
trigger hormones called EPO that will send signals to the bone marrow
briefly explain the physiological variables in diet
glucose, lipids and electrolytes
effective way to replace fluids and essential salts lost due to dehydration
ORS, oral rehydrating solution
diurnal vs circadian
diurnal:
happening daily
circadian:
having a 24 cycle
Factors that play a role in diurnal
variation include
Posture (whether you’re sitting, standing, or lying down)
Activity (moving around vs. resting)
Eating (before or after meals)
Daylight and darkness (being in natural light vs. nighttime)
Sleep patterns (whether you’re awake or asleep)
briefly explain the certain substances in the body change throughout the day in diurnal/ circadian variation
index card
briefly explain the physiological variables in drug therapy
index card
briefly explain the physiological variables in exercise
index card
briefly explain the physiological variables on what the exercise depends on
patient’s physical condition
duration and intensity of the activity
in general, how long can the drugs interfere with blood tests
blood: 4 - 24 hours
urine: 48 - 72 hours
why is it not allowed to pump the fist during venipuncture
as this simple exercise is enough to erroneously (falsely) increase potassium levels
Potassium is mainly found inside your cells, including muscle cells.
Pumping your fist can trick the test into thinking you have more potassium in your blood than you really do. This can lead to confusion and unnecessary medical steps, so it’s best to keep your arm still and let the needle do its job without any extra muscle movement
briefly explain the physiological variables in fever
have physiological and hormonal changes
fever induced hypoglycemia (glucose lvl to drop)
increases insulin levels (take in sugar from your blood )
followed y rise in glucagon lvls (release stored sugar into blood)
↑ cortisol
- a stress hormone
- aka emergency hormone
- when we have fever, it releases cortisol and increase insulin (which decreases blood glucose level)
briefly explain why males have different normal values compared to females
males have higher normal values of rbc, hematocrit and hemoglobin
factors that influence:
-body composition
-hormones, testosterone
briefly explain the physiological variables in intramuscular injection
↑ CK & LDH
*recommended that CK & LDH to be drawn before intramuscular injection or at least 1hr after
what increases the CK level
muscular trauma or surgery
it is a condition characterized by increased bilirubin in the blood
jaundice
it is a yellow bile pigment that is the product o the destruction of RBCs and the breakdown of the hemoglobin they contain
bilirubin
it is relating to jaundice and it is used to describe serum, plasma or urine specimens that have an abnnormol color, what color are they
icteric
deep yellow to yellow-brown color
- due to high lvls of bilirubin
jaundice in a patient may indicate …
liver inflammation caused by hepatitis B or C virus
briefly explain the physiological variables in position, supine (lying down on the back) to an upright sitting or standing position
up to 10% ↓ of plasma volume in adult
↑ aldosterone, bilirubin, body cells, cholesterol, Ca, Fe, renin
K+ ↑ in prolonged standing (30mmin)
briefly explain the physiological variables in position, lying to sitting
↑ high-density lipoprotein and cholesterol
up to 10-12% ↑ triglycerides
↑ 2 hormones - aldosterone and renin
this could change slowly but double within an hour in a plasma
aldosterone and renin
hence,
If doctors want to measure aldosterone accurately, they need you to lie down for at least 30 minutes before taking the blood sample.
- when testing for plasma renin activity, doctors need to write down whether you were lying down or standing up when they took the blood as your position affects the result
briefly explain the physiological variables in pregnancy
of increased plasma volume/ fluid volume (amniotic fluid)
- clear liquid that surrounds and protects a developing baby in the womb
there is dilutional effect
-how blood level increase - which makes subs in blood seem lower than they actually are, bcs they r spread out
briefly explain the physiological variables in smoking
↑
cholesterol, cortisol
glucose, growth hormone
triglycerides
rbc, hemoglobin, wbc
Immunoglobulin E (IgE)
BUN - waste product formed when protein is broken down
catecholamines - hormones made by adrenal glands and nerve tissues (fight or flight response enzymes )
↓
Immunoglobulin G, A, M ( IgG, IgA, IgM)
pulmonary function
briefly explain the physiological variables in stress
stress - anxiety, fear, trauma
↑ WBC
- crying infants, will return within 1hr after crying stopped
- ideally collect when infant is sleeping or rest quietly for at least 30 min
* note on the report if an infant is crying
↑
Adrenocorticotropic hormone catecholamines - hormones made by adrenal glands and nerve tissues (fight or flight response enzymes )
Cortisol
ABG, arterial blood gas
lactate
fatty acids
briefly explain the physiological variables in temperature and humidity
acute heat exposure causes interstitial fluid to move into the blood vessels, ↑ plasma vol and influence its composition
extensive sweating without replacement = hemoconcentration
how does ne transport specimens drawn at off-site locations (etc. homes/ nursing homes)
first they should require when interpreting results, they should consider the other geographic influence
next they require protection from temperature extremes to preserve the specimen integrity
This site’s veins are difficult to palpate
Burns, scars and tattoos
Why do we have to avoid burned and scarred sites
Healed burned and other areas with extensive scarring - impaired circulation (blood isn’t flowing properly) that may lead to erroneous (invalid) test result
New burns - painful and susceptible to infection
Why do we have to avoid tattoo sites
Undetected infection
More susceptible to infection
tattoo can cover up areas of the skin, making it harder to see if there are any problems like bruises, rashes, or reactions from a blood draw - impair the ability to detect bruising , rashes etc
What happens if you have no choice to draw in an area with a tattoo
Insert the needle in a spot that does not contain dye
Why does some patients’ vein feel hard and cordlike and lack resiliency
As they are partially or completely occluded (obstructed)
- these veins are sclerosed (hardened) or thrombosed (clotted)
From the effects of inflammation, disease or chemotherapy drugs
What causes scarring in veins
Numerous venipuncture
Where do we venipuncture if there is a damaged veins
Another site or draw blood below (distal to) damaged veins
Swelling caused by the abnormal accumulation of fluid in the tissues
Edema
- sometimes result when fluid from an IV infiltrates the surrounding tissues
- veins are harder to locate and stretched tissue is fragile
More easily injured by
Tourniquet
Antiseptic application
Healing may be prolonged
Remedy if 2 arms have IV fluid inserted
Ask the nurse to lock (stop) the flow of 1 IV fluid for at least 5minutes
Draw 10ml of blood
- 5ml of blood should be discarded
- remaining can be used
- use ETS or butterfly method not syringe
How to ensure the collection of noncontaminated blood
Never perform venipuncture through a hematoma
If no alternative site, perform the venipuncture blow (distal to) the hematoma to ensure the collection of free flowing blood
Surgical breast removal
mastectomy
It is a swelling or a mass of blood (often clotted) and what causes it
Hematoma
Caused by blood leaking from the blood vessels during or following venipuncture
A large bruise eventually spreads over the surrounding area
- painful
- contaminate blood sample
- obstruct blood flow
It is obstructed with the removal of lymph node, which is typically part of the procedure - mastectomy
Lymphostasis
- could change blood composition and lead to inaccurate test result
Impaired lymph flow makes the arm susceptible to swelling
Lymphedema
- swelling and infection may be present
*applying tourniquet can cause injury
What happens if masectomy has been performed on both sides or there is no suitalble site for blood collection other than an ar, on a masectomy side
Obtain written permission from the patient’s physician for the blood draw on that arm
What are the problems faced when drawing blood in obese patients and how to resolve it
● Veins may be deep and hard to find.
● Use bariatric tourniquet and try median cubical or cephalic vein.
Or extra large size blood pressure cuff , provided it is inflated to just below the patient’s diastolic pressure
A medical word that originally meant prelates ro treating obesity. But now, people often use it as a nicer way to talk about things for very overweight people, even if they’re not getting medical treatment
Bariatric
It is the loss of muscle function that can be temporary or permanent. It can be localized or widespread.
What causes it
Paralysis
Causes:
Stroke
Spinal cord injury
Nerve damage
Muscular dystrophy
Amyotrophic lateral sclerosis
Why should it not be assumed that there is no feeling in a paralyzed arm
ll. If the nerves that carry sensation are damaged, then the person won’t feel anything. But if the nerves are okay, the arm might still have some feeling, even if it can’t move. So, it’s important not to assume there’s no feeling without checking for nerve damage.
When lower part of the body and both legs are paralyzed
Paraplegia
Both arms and legs are paralyzed
Quadriplegia
What must be done if the patient is allergic to
Adhesive allergy:
Antiseptic allergy:
Latex allergy:
Adhesive allergy:
place gauze square over site; have patient remove it in 15 minutes.
Or have patient apply pressure for 5 minutes instead of bandage.
Antiseptic allergy:
use alternate antiseptic
Latex allergy:
look for sign on patient’s door; use non latex equipment
Why do some patients have excessive bleeding
As patients on aspirin or anticoagulant therapy may bleed longer
Maintain pressure until building stops. cannot leave patients until bleeding has stopped
True or false:
use a pressure bandage as a quick fix for bleeding
False - Never use a pressure bandage as a quick fix for bleeding. You should keep applying pressure until the bleeding stops. Don’t leave a patient or send them home until the bleeding is fully under control or until the right medical staff have taken over. This ensures the person gets the care they need.
Temporary loss of consciousness and postural tone
Fainting (syncope)
Caused by insufficient blood flow to the brain
Lasts for only a few seconds or as long as half an hour
- During venipuncture, ask patients with a history of fainting to lie down.
What are the contributing factors on why patient faint
● Anemia
● Dehydration
● Emotional problems
● Fatigue
● Hypoglycemia
● Hyperventilation
● Medications
● Nausea
● Needle phobia
● Poor or compromised breathing
Why should we not use ammonia inhalants to revive patients who fainted
As they can have unwanted side effects like respiratory distress in asthmatic individuals
Sudden faintness or loss of consciousness caused by a nervous system response to abrupt pain, stress or trauma is a type of reflex syncope
Vasovagal
When do we discontinue blood draw until patient feels better
When patient is feeling nausea and vomiting
What should we do if a patient is feeling nauseas and vomits
○ Give the patient an emesis basin or wastebasket.
○ Apply cold, damp washcloth to forehead.
Why do we need to warn patient before needle insertion
To avoid startle reflex
Why is it required to allow the alcohol to dry completely before needle insertion
To avoid causing a stinging sensation
What causes pain when needle is inserted
Excessive, deep, blind or lateral redirection of the needle
*extreme pain or numbness indicated nerve involvement
They are tiny, nonraised red, purple or brownish spots that appear on the patient’s skin when a tourniquet is applied
Petchiae
- the spots are minute drops of blood that escape the capillaries and come out to the surface of the skin below the tourniquet
Nonraisedblood spots larger than 5mm
Ecchymoses
What to do when a patient is experiencing seizures/ convulsions
○ Discontinue drawing immediately.
○ Hold pressure over site without restricting patient’s movement. (On the floor and turn them to one side to keep the airway clear, put smthing soft under their head)
○ Do not put anything in the patient’s mouth.
○ Protect patients from self-injury.
○ Notify first air personnel.
*time the seizure
a decreased in fluid content of the blood
hemoconcentration
- increased in nonfilterable large molecules
- caused by stagnation of normal venous blood flow due to torniquet application
what causes hemoconcentration
Heavy massaging of the site
probing for veins
long term IV therapy
drawing blood from
sclerosed or occluded veins
vigorous hand pumping (making
and releasing a fist).
damage to or destruction of rbc
hemolysis
- hemoglobin escapes into fluid part of the specimen
slight hemolysis =
moderate hemolysis =
gross hemolysis =
slight hemolysis = pink
moderate hemolysis = dark pink to light red
gross hemolysis = dark red
blood to additive ratio may be incorrect
partially filled tubes (short draws)
additive to WB ratio 1:9 (sodium citrate anticoagulant)
excess edta (lavender) -
excess heparin (green) -
excess sodium fluoride (gray) -
underfilled coagulation tubes -
excess edta (lavender) - shrink rbc = erroneously low blood cell count and hematocrits
excess heparin (green) - interfere chem analytes
excess sodium fluoride (gray) - hemolysis
underfilled coagulation tubes -do not have correct blood to ratio = erroneous results
why should we never pour two partially filled additive tubes together to fill one tube
affect the blood-to-additive ratio
Results of improper technique or carelessness.
specimen collection
(examples:
allowing alcohol residue, fingerprints, glove powder, baby powder, urine on newborn screening samples
getting glove powder on blood films or capillary specimens.
dripping perspiration into capillary specimens.
following improper antiseptics procedure
use wrong antiseptics)
what happens if you use wrong or expired collection tube
formation of microclots
may hv lost the vacuum
what are the troubleshooting failed venipuncture in tube position
improper seating
needle fails to penetrate stopper
remember: STOP, ASSESS & CORRECT
what are the troubleshooting failed venipuncture in tube vacuum
loss of vacuum due to bevel partially out of the skin or damage to the tube
