Basic Laboratory Testing Flashcards
what is the definition of sensitivity?
the measure of the tests ability to detect persons who have a disease or condition (true positive)
What is the definition of specificity?
the measure of how well the test excludes the possibility of of a particular disease (true negatives)
between sensitive and specificity, which is attempted to be maximized by laboratory testing.
maximize specificity
what is hemolysis?
rupture of RBC, classified as slight, moderate, or severe, based on amount of hemoglohin present in serum.
what is Lipemia?
presence of high concentration of lipids in serum.
what are the two origins of lipemia?
- due to postprandial hyperlipidemic following a high-fat meal
- genetic make-up (uncommon)
what is glycolysis?
the breakdown of glucose.
what tests provide a more reliable estimate of average glucose levels?
Fructosamine and HB A1C.
what is
- mg/dL
- ug/ml
- IU/L
- miligram per 100ml sample
- microgram/milliliter
- enzyme activity, International units/liter.
Most of the world has switched to “S.I” units. Name 2 examples.
U/L and mmol/L
what is Venipuncture?
blood drawn from a vein, obtained by PM, phlebotomist, nurses, or doctors.
what is dried blood spot?
the side of the finger is puncures with a lancet and as droplets of blood form, the droplets are transferred to a small piece of blotting paper. used fo HIV
saliva and urine?
lower policy amounts, and certin risk assessments. Saliva detexts HIV, cotinine, cocaine.
what tests can be collected form an AOR?
saliva and urine.
what is the typical transport time for blood? (seperation of serum from CBC)
2 days. `
what is the standard deviation?
it refers to the normal variation in personal biologic set point and reflects differences in the genetic background of people. the reference range includes 95% of the population.
on what basis is relative risk based on?
its based on a comparison to the standard mortality of he same age applicant.
how is pricing for insurance products determined?
based on average mortality based on age. increased risk indicates a higher risk of death compared to the STD risj.
what is evaluated through a basic urine sample?
drugs, nicotine, creatining, protein, glucose and blood cells, antibodies.
what is evaluated through a saliva sample?
HIV, cotinine, and cocaine.
what is a reflex test, and when would you order one?
reflexive testing is run following abnormal levels in the BW. ^ ALT > hepatitis screnning is run, an alcohol screening is run for elevated HDL and liver enzymes.
how long is a urine sample typically held?
4-5 weeks. ,
what is the best measure of renal filtration function in a urinalysis
GFR- glomerular filtration rate, we can be measured by excretion of an injected dye or radionucleotide. eGFR is typically used in u/w process.
how is eGFR calculated?
using age, sex, and the serum creatinine measurement from the blood
what is creatinine, and what is the average dispenced amount by people?
the breakdown product of muscle metabolism. average 1g per day.
why is creatinine used to adjust for variation in urine samples?
it is a steadied pace, and typically urine concentration can vary based on fluid intake, but using creatinine as a based of [ ] for comparison allows for more consistent results. `
what is the best method to determine concentration changes?
by using the rations such as protein/creatinine, and albumin/creatinine.
some people will try to adjust their urine levels to read lower/ negative readings. what is the creatinine minimum we will accept, before asking for a new sample/investigate (women vx men)
women 9mg/dL
men 11mg/dL
what amount of proteinuria is associated with excess mortality
150mg/day
what form of protein is not detected by urinalysis?
globulin
A sample positive for proteinuria can become negative when what calculation is applied, and why?
urine is more concentrated in the morning than at night, so we apply the creatitine calculation.
what disease tipicallt causes an excess of albuminuria?
glomerular disease, followed by kidney disdease, damage to kidney from HTN, and tubular proteinuria.
Which disease has a great increase of mortality when albuminuria is present?
diabetes- d/t cardiovascular mortality
albumin makes up approx. one half of urinary protein excretion. What diease, causes that percentage to increase
kidney disease. early stages, cause minor changes, when the level is between 30-300, the condition is microalbuminuria, when its above that its called albuminuria.
IF urine test +ve for glucose what test is reflexed on the BW?
A1C.
when should a blood sample be collected, in terms of amount of glucose in the urine?
when its greater than 0.05g/dL.
what is leukocyte esterase, and hemoglobin?
an ezyme present in WBC, a protein present in RBC.
If a urine test is +ve for Leukocyte esterase
examined by flow cytometery (sophisticated automated microscope) to count RBC and WBC.
what are some possible explinations to why there is hematuria?
infection, glomerulonephritis, kidney-ca, and UTI, disease of metabolism, or possible collection of adftifact in menstruating females.
what is the magic number of RBC to be considered a risk?
> 9
what level of hematuria appears to be associated with increased risk for females > 60 years old or less?
none
what are urine casts?
aggregates of proteins or red or white cells. theyre formed from the inside wall of the kidney tubules.
in 2010, what was the leading cause of accidental death in young females?
opiate overdose.
many drug samplings are the same, use cocaine as an example. How is cocaine usage determined?
when sample is +Ve for metabolits, the presence is varified by gas chromatography mass spectroscopy (GCMS) or by LCMSMS,. each drug produces a unique finger print.
Every insurance company tests for cocaine, what are some other common tests run by insurance companies?
marijuana, and amphetamine. The following are just common drugs of abuse:
opiates, PCP, barbituates,
what is the half-life of nicotine (through the blood system)
one to two hours, but a smoker will typically test positive for cotinine 1-3 days after last sue.