Clin lab test 1 Flashcards
1998 CLIA (Clinical Laboratory improvement) did what to deficiencies? How?
Decreased deficiencies by 40%. Established standards related to accuracy, reliability and timeliness.
What are the three parts of the EBM triad?
- Individual clinical expertise
- Best external evidence
- Patient values and expectations
Gray top tube is used for what? What type of additives are in the tube?
Blood alcohol, glucose. Sodium flouride (glucose preservative) and Potassium oxylate
Green Top has an anticoagulant. True or false? What is it?
True, Heparin
Lab pathology is divided into two subsections, what are they?
Anatomic and clinical.
Clinical pathology is divided into what 6 sections
Microbiology, UA, hematology, chemistry, serology, immunohematology
Light blue top tube has what in it?
Sodium citrate (9:1)
Light blue top goes to what lab section?
Hemotology, coagulation
What is the primary and secondary function of the chemical laboratory
Generate info and educate providers/staff.
What is the second most common lab sample
capillary pull
What is the role of medical laboratory testing?
Detect, diagnose, treat
What are the 5 criteria for testing complexity under clia 98?
- Risk of harm to the patient. 2. Risk of erroneous result. 3. Type of testing method used. 4. Degree of independent judgment and interpretation. 5. availability for home use.
What are the four categories of test complexity?
Waived (minimal)
Moderate (includes PPM)
High
What are the three types of unacceptable blood specimens?
Icteric (jaundiced)
Lipemic
Hemolyzed (processing error)
What color tube is used for a CBC? What anticoagulant is in it?
Lavender, EDTA
What determines a good screening test? What about a good confirmatory test?
Screen: Sensitivity and NPV high
Confirm: Specificity and PPV high
Define PPV, Define NPV
TP/TP+FP positive result actually positive ratio
TN/TN+FN negative result actually neg ratio
What is the best site for venipuncture
Median cubital vein
What is the most common specimen submitted to the laboratory
Venous blood samples
What is the order of draw for tubes based on color? What are the associated inversions for each?
- Yellow 8-10
- light blue 3-4
- gold/red/grey 5, red (plastic) 5, red (glass) 0, Orange 5-6
- Light Green, Green 8-10 (For all following as well)
- lavender
- white
- gray
A BMP (basic metabolic panel) consists of what tests?
Sodium, Potassium, Chloride, CO2 (Bicarb)
Blood Urea Nitrogen, Serum Creatinine, Serum Glucose, Total Calcium
A BMP is typically collected in what vial?
Red (slides say Light green, gold as well)
Hypernatremia always indicates what in relation to body water?
Relative total body water deficit
(Among other things…) Hyponatremia is found in what?
Hypernatremia is found in what?
Addison’s
Cushings
Hyperkalemia leads to ______?
Aldosterone secretion and K excretion
Hyperkalemia is associated with
Prim/Sec hypoaldosteronism
Hypokalemia is associated with
Diabetes mellitus, Cushings, Hyperaldosteronism.
Hyper and hypochloremia are generally tied to what?
Shifts in sodium and bicarb. Cl shifts to maintain electrical neutrality
Increased HCO3 is indicative of what disorder?
Metabolic alkalosis; Primary or secondary to Respiratory acidosis
Decreased Bicarb in BMP is associated with what disorder?
Metabolic acidosis
Increased blood urea nitrogen on a panel is indicitave of disorder with what organ? What could be happening?
Kidneys. Decreased GFR/Increased tubular reabsorption, inadequate excretion, or increased gut production from too much protein or blood.
Serum calcium is tied to changes in what?
Serum albumin
A Complete metabolic panel includes what tests?
All BMP plus albumin, alanine transaminase (ALT), Alkaline phosphatase (ALP), Aspartate aminotransferase (AST), Bilirubin, Total protein
Albumin comprises _______ percent of total extracellular blood protein. It is a measure of ______ function
60%
Hepatic
Increased ALT mainly signifies what?
Increased ALP signifies what?
Damage to the liver (though remember skeletal muscles too)
liver or bone disorders
AST is most commonly a reflection of what?
If AST is >2 x the ALT, what should you suspect?
Liver injury
Alcohol abuse w/ cirrhosis or alcoholic hepatitis
Total protein measures what 2 classes of protein?
Albumin and globulin
CBC contains what information?
Include critical values
Total RBC Hemoglobin Hematocrit (RBC volume of total blood) Mean Corpuscular value (avg size of RBC) Mean Corpuscular Hemoglobin MCHC (proportion of cell occupied by hemoglobin --color) RBC distribution width (variation in RBC size) WBC count (crit - <2k or >30k) Platelets (crit - <20k)
UA panel consists of what 10 tests?
Specific gravity pH Protein (kidneys) Glucose Ketones Blood (ketones vs. trauma) Leucocyte esterase (infection) Nitrite (bacterial metabolism product) Bilirubin Urobilinogen (formed from bilirubin in intestine)
What are desirable and high levels for Total Cholesterol?
D: less than 200 mg/dl
High: 240+
What are desirable and high levels for fasting triglycerides?
D: Less than 150 mg/dl
High: 200-500
VH: 500+
What are desirable and high levels of LDL and HDL
LDL
Desirable: less than 100mg/dl
High 160-189
HDL:
Desirable:60mg/dl both men and women or MORE
Low: less than 40 for men and 50 for women.
Up to 70% of lab errors occur during what phase of testing?
Pre-analytical
A critical test value must be reported in what timeframe? What about a STAT test result?
Crit: 1 hour from completion
STAT: 1 hour from receipt of order
What is a reflex test?
An automatic test conducted by the lab in the event of a specific positive first test.
Describe cortisol’s diurnal variation
Peaks 4-6 AM
Lowest @ 8PM-12AM
50% lower at 8 PM than AM
When is insulin lowest, night or daytime?
Night
Iron peaks when? How much does it decrease following its peak?
Early to late morning
Decrease by up to 30% during the day.
What are 10 common errors in specimen collection?
Mis-ID of patient Mislabel specimen Bad draw/wrong ratio Mixing problems/clots wrong tubes Hemolysis/Lipemia Hemoconcentration from TQ Exposure to light and high temps improper timing Processing errors
What are 10 rejection criteria of drawn samples?
Improper collection and label Prolonged transport - degraded Leakage Incomplete request Clotted/hemolysis/insuff quantity Non-fasted Improper preservation Unprot from light Acidified Non-Frozen
Platelets, erythrocytes, and leukocytes are ______ found in plasma?
What about serum?
Not
Still no, serum contains most of the same things as plasma except for fibrinogen
Instrument failure is an example of ___________ error
Analytical
Instrument failure is a part of _______ failure within _______ causes of error. It consists of what three types?
Measuring system; Analytical
- Software failure
- Optics drift
- Electronic instability
What are the three causes of Inadequate instrument maintenance error?
- Dirty optics
- Contamination
- Scratches
What are 5 examples of analytical errors from the slideshow?
Failure to notice instrument flags Disregarding OOC quality control results Wrong assay performed Test performed incorrectly no test performed, but result produced
Examples of post-analytical errors include what?
Incorrect verbal reporting of critical/alert values Instrument interface incompatible reference range confusion wrong results reported transposed results during entry incorrect interpretation
Point of care testing requires what?
Documented training
CLIA requirements have incorporated what to ensure proficiency of laboratories?
Quality assessment proficiency testing
Labs get sent outside samples, don’t cheat.
What are the four indicators of reliability/validity of a clinical laboratory test? How are they broken down?
- Precision
- Accuracy (1 and 2 = how test performs day-day)
- Sensitivity
- Specificity (3 and 4 = how well the test is able to distinguish disease from absence of disease.
What is precision? What is Accuracy?
Precision - repeatability (low variation = high precision)
Accuracy - Trueness (Test value being close to “True” value = high accuracy)
A test that is more __________ will result in fewer false negative results?
Sensitive
How is prevalence related to PPV?
High prevalence = High PPV
Low prevalence = High NPV
What percent of a healthy population will yield an abnormal test result?
5%
What are the three primary accrediting bodies for laboratories?
Commission on office laboratory
College of American pathologists
The Joint Commission
To meet the criteria of PPM testing, these specifications must be met (6)
Exam must be performed by a provider Procedure must be moderate complexity Primary instrument must be microscope Specimen is labile Control materials are not available Handling of specimen is limited
Decreased ionized calcium produces what results? (2)
Impaired cardiac function and tetany
If the kidney is impaired, concentration of urea in the blood is what? Why? What can this also be dependent on?
Increased
Urea is a waste product from ammonia in the liver, it should be excreted.
Protein intake
Clearance of creatinine from the plasma by the kidney is a measure of what?
GFR
What are 3 common chemistry tests performed on CSF samples?
Protein
Glucose
Lactate
Page 456
In addition to chemistry tests, what 2 other tests are common with a CSF sample?
Microbiological exam (staining and culture) Serology (syphilis)
A darkfield microscope typically is used for viewing _______. How does the darkfield’s use of light compare to regular microscope?
Spirochetes
Background dark, specimen bright (opposite regular)
What is a saline wet prep?
What is its other name?
Provider performed microscopic test. Usually vaginal smears for Trichomonads, clue cells, and yeast.
Direct wet mount
What is a clue cell?
An epithelial cell that has been covered in bacteria giving it a sandy appearance. Cutoff for clue vs. non clue is detection of nucleus
Yeast can be found with two presentations. What are they?
Budding (shoeprint)
Pseudohyphae
After a saline prep, we can do a KOH prep. Why?
What kind of test is this?
Dissolve tissue materials so that only fungal elements remain.
PPM (Moderate)
What is a Fern test? What type of test is it?
A PPM test to determine presence of amniotic fluid/determine rupture of fetal membranes before labor onset.
What are we evaluating in a postcoital test (PCT)?
Infertility
Finding an increase of what WBC on a nasal smear will indicate allergic rhinitis?
Eosinophils
A rapid flu test is an example of what class of testing?
POC/Waived
A major advantage of POC testing is what?
A. Faster turnaround time
B. Lower cost
C. ease of use
D. both a and b
Faster turn around time. POCT is more expensive in general.
Over the counter tests approved by the FDA (so… legal) are automatically placed in what CLIA catagory?
Waived/minimal
Tests for fecal occult blood are in general use as a screening test for which of the following?
Breast cancer
Colorectal cancer
Enteric infection of the colon
Malabsorption syndrome
Colorectal cancer
What is the goal of therapeutic drug monitoring?
Increase the likelihood of a therapeutic effect and avoid or minimize adverse effects
What is therapeutic drug monitoring?
The practice of measuring the concentration of a drug or its metabolite to aid in the correct dosing and/or assess patient compliance with prescribed regimen
What is an unpredictable dose response?
When the same dose produces therapeutic effect in one patient and toxic effect in another. Also when dose produces a response beyond anticipated.
What are the two most common carrier proteins for insoluble drugs?
Albumin
Alpha1-acid glycoprotein
Presence of any liver disease will do what to the free fraction of drugs?
Increase it
What is the free fraction of a drug?
Therapeutically (biologically) active fraction of the drug. (Not protein bound)
Define therapeutic range
Range where probobility of desired response is high and probability of unacceptable toxicity is low. MEC vs MTC
What is the trough value of a drug?
Lowest therapeutic concentration achieved during dosing cycle. Still in therapeutic range
After initiation of drug therapy, how many half lives are required to reach nearly complete (97%) steady state concentration?
5
What is steady state concentration?
Steady state = drug entering in equilibrium with drug eliminated.
Primary site of drug metabolism is the _________.
Liver
Therapeutic drug monitoring is done utilizing a _______ tube and _________ sample
red; serum
Describe the acute range of toxicity for Aspirin
Acute <150 mg/kg - no toxic rxn expected 150-300 mild to moderate 300-500 serious >500 potentially lethal ~660 average fatal
Describe chronic ingestion toxicity for aspirin
Ingest >100mg/kg/day for at least 2 days
What is the timing of monitoring for aminoglycosides in traditional dosing (q8H) and once daily dosing?
Trad - Peak : 1 hour after infusion complete
Trough: ~30 minutes prior to the next dose
Once-daily - 6-14 hours after the 1st infusion
What are the 5 functions of CSF?
Transport of nutrients (hypothalamus releasing factors)
Mechanical barrier to cushion brain and spinal cord
Excretory waste function
Protect against sudden venous and arterial pressure changes
Maintain ionic homeostasis for CNS via BBB
List 4 CSF testing indications.
Meningeal infection
Brain hemorrhage
primary or metastatic malignancy
Neuro disease
The most common type of encephalitis is
Viral
Describe how to collect CSF.
Puncture interspace of vertebrae L3/L4 or lower
Attach manometer through stopcock, not opening pressure (5-20cm h20)
Collect at least 10 drops of CSF in each 4 tubes up to 20 ml total.
Send tubes to lab. THIS is a STAT test.
Describe the 4 collection tube tests for CSF
Tube 1 = chemical and serologic (frozen)
Tube 2 = microbiology (room temp)
Tube 3 = hematology (refrigerate)
Tube 4 = Micro or additional serological
What are the s/s for meningitis?
Sudden fever, severe headache, N/V, Double vision,. drowsiness, sensitivity to light, stiff neck
What are the s/s for encephalitis?
Fever, seizure, change in behavior, confusion and disorientation.
Describe CSF levels in terms of protein, glucose, glutamine and lactate chemistry tests
Increased protein = meningitis, hemorrhage and MS
Decrease protein = fluid leak
Decreased glucose = bacterial meningitis , fungal and maybe parasitic
Increased Glutamine = liver disorder
Increased lactate - bacterial, fungal, and tubercular meningitis.
CSF is usually what color? What about serous fluids?
Clear/colorless
Pale and yellow (straw)
Differentiate transudate and exudate
Transudate is formed from a systemic disorder disrupting regulation of filtration and reabsorption
Exudates are produced by conditions that directly involve membranes of a cavity
Chest pain (sharp or dull) that is relieved by bending forward, hearty rhythm changes or cardiomegaly o x-ray would lead to ordering what test?
Pericardial fluid analysis to r/o pericardial effusion and related pathology.
Protein concentration is _________ in exudates compared to transudates.
Increased
Elevated protein = ___________ glucose in serous fluid
decreased due to high leukocyte count
LDH is _________ in exudates
Increased
