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)