Exam 1 - clinical chem

clinical chemistry

* a science, a service and an industry
* science to link the knowledge of general chem, organic, chem, and biochem with am understanding of human physiology
* service to produce objective evidence from which medical decisions are made
* industry of businesses which operate under the regulation and practices that guide commerce

laboratory operations

* regulations, policies and procedures
* regulations to govern and standardize
* policies for organization guidelines
* procedures for standard practices

cognitive

acquiring and applying knowledge

psychomotor

ability to perform tasks or skills

performance measurements

affective

attitudes or feelings

work ethics, professionalism, interpersonal skills

how is knowledge mastery obtained

learning requires the whole body for knowledge mastery

cognitive: levels of understanding

1. knowledge - recall, remember
2. comprehension - explain, grasp
3. application - calculate, operate, solve
4. analysis - identity, diagram
5. synthesis - create, design, modify
6. evaluation - interpret, criticize, compare

psychomotor

1. reflex movements
2. basic fundamental movements
3. perceptual abilities
4. physical abilities
5. skilled movements
6. non-discursive movement - independent no supervision

affective - levels of feeling

1. receiving
2. responding
3. valuing
4. organization
5. characterization

what level of psychomotor development does MLT obtain

6. non-discursive movement - independent no supervision

what does OSHA represent

occupational safety and health act - federal responsibility

what does OSHA do

* federal regulation enacted in 1970
* provides employees with safe work
* on-site inspections to ensure compliance
* administered by state agencies or federal administration
* includes standards that regulate safety in many aspects of clinical laboratory

employer’s responsibilities

* establish written laboratory work methods and safety policies
* provide safety information, supervision, guidance, training, protective equipment, medical surveillance to employees
* provide and maintain adequate equipment and facilities

employee’s responsibilities

* know and comply with work safety methods
* notify supervisors of unsafe conditions/practices
* use personal protective equipment

why is safety labeling important

identify hazards because of emergencies such as fire or explosions

what association created the standard for hazard identification system

national fire protection association (NFPA)

how are reagents and solutions labeled

* chemical identity
* concentration
* hazard warning
* special handling
* storage conditions
* date prepared
* expiration date
* preparer’s initials

NFPA hazard label

* blue - health
* red - flammability
* yellow - stability
* white - special hazard
* magnitude of severity, graded from a low 0 to a high 4

class A fires

ordinary combustibles: wood, paper, cloth etc.

how are class A fires extinguished

pressurized water

dry chemical

class B fires

flammable, liquid, grease, gasoline, paints, oils etc.

how are class B fires extinguished

dry chemical and carbon dioxide

class C fires

electrical equipment, motors switches

how are class C fires extinguished

carbon dioxide, halon, dry chemical

class D fires

flammable metals, magnesium

how are class D fires extinguished

metal X - cover burning materials with extinguishing agent (scoop sprinkle)

what is lab universal precautions

all blood and body fluids are considered infectious

biohazardous waste

* establish and implement and infectious waste program
* bag marked with biohazard symbol and then into a leakproof, puncture - resistant container with tight-fitting lid
* place sharps into special puncture resistant container
* never transport, recap, bend or break by hand needles

disinfecting procedure

clean and sanitize all work surfaces at the beginning and end shift with a 1:10 dilutions of household bleach

clinical laboratory improvement amendments of 1988 (CLIA)

* protection for lab staff, health care personnel and patients
* all laboratories must have a CLIA certificate to perform testing and receive federal reimbursement

public health service act

allow lab payment from Medicare and Medicaid

centers for Medicare and Medicaid services (CMS)

license labs to receive Medicare and Medicaid payments

clinical and laboratory standard institute (CLSI)

voluntary consensus standards for laboratories

what does the AACC represent

American Association for Clinical Chemistry

what does the FDA represent

Food and Drug Administration

what does the NACB represent

National Academy of Clinical Biochemistry

what does the OIVD represent

Office of In Vitro Diagnostic Device Evaluation and Safety

what is the criteria for CLIA classification

1. risk of harm to the patient
2. risk of an erroneous result
3. type of testing method used
4. degree of independent judgement and interpretation needed
5. availability of the particular test in question for home use

what are the categories of complexity

* waived
* provider-performed microscopy
* moderately complexity
* highly complexity

Waived

* cleared by the FDA for home use
* simple that the likelihood of erroneous results is negligible
* pose no reasonable risk of harm to the patient if the test is performed incorrectly
* test: urine pregnancy

provider-performed microscopy

* examination preformed by practitioner
* categorized as moderately complex
* instrument: microscope
* specimen is labile
* control materials are not available
* specimen handling is limited
* tests: semen analysis, fecal leukocyte examinations

highly regulated

moderately complex: gram stain, automated lab tests

highly complex: manual differential, nonautomated chemistry tests

point-of-care testing

* decentralization of testing away from laboratory
* at patients bedside
* clinics
* not always performed by laboratory staff
* CLIA regulations apply

proficiency testing (PT)

is a mandatory for all moderately and highly complex

quality assessment (QA)

is a comprehensive set of policies, procedures and practices that are followed to ensure that a laboratory’s results are reliable

* evaluates the quality of the services provided
* provides a way to prevent problems as well as deal with a problems that occur
* includes record keeping, maintenance and calibration of equipment, proficiency testing, quality control and training of personnel
* commitment to quality

Point-of-Care Testing (POCT)

decentralization of testing away from laboratory

* at patients bedside
* clinics

accuracy

test result close to true value

calibration

instrument comparison to a known standard

control

specimen with known value

precision

test result close to each other

standards

purified substances of known value and composition to best measure accuracy

quality control

is a process that monitors the accuracy and reproducibility of results through the use of control specimens

critical values and delta check syst

to monitor individual patient results

what are two major components of quality assessment

nonanalytical factors

analysis of quantitative data (quality control)

nonanalytical factors

personnel, policies, procedures, methods, equipment maintenance

quality control

oversees each procedure for an established protocol to ensure the quality of the results

what does CAP represent

College of American Pathologist

what is the best to describe systemic error

variation that may make results consistently higher or lower than the mean value for a control

consistent in one direction (higher or lower)

constant proportional

Gaussian distribution

normal distribution, total area under curve is 1.0 or 100%

bell-shaped curve, uniform

probabilities of the SDs

* mean +/- 0.5 SD, 38.38%
* mean +/- 1.0 SD, 68.20%
* mean +/- 2.0,SD,95.50%
* mean +/- 3.0 SD, 99.70

pre-analytical

sick patient → M.D. orders → collection → transportation

Analytical

analysis → data flow

post-analytical

interpretation by M.D. → diagnosis and treatment → healthy patient

range

largest value in the data minus the smallest value

represents the extremes of data

standard deviation

represents the “average” distance from the center of the data (the mean) and every value in the data

coefficient variation (CV)

compare SDs with different units and reflects the SDs in percentages

standard deviation index (SDI)

the number of SDs a value is from the target men

variance

is the average of the squared distances of all values from the mean

* measure of dispersion, variance represents the difference between each value and the average of the data

interference studies

designed to determine if specific compounds affect the accuracy of lab tests

* ex: hemolysis (broken

diagnostic sensitivity

ability of a test to detect a disease

true positive over true positives + false negative

* more false negatives = larger denominator, smaller ratio

diagnostic specificity

ability of a test to identify the absence of a given disease

\# of negative tests when no disease present over # of negative test + # of false positives

TN/(TN + FP)

more false positives means a larger denominator, small ratio

positive predicted value

probability of an individual with the disease having a positive test

PPV (%) = TP/ (TP + FP)

more false positives = larger denominator

negative predicted value

probability that an individual with a negative test does not have the disease

NPV (%) = TN / (TN + FN)

reference intervals

\- all data points that define the range of observations

\- decision points that span the limits of results expected for a defined healthy population

normal range

points that correspond to the central 95% of results from a heathy patient population

SI units for volume

cubic meter (m3)

SI unit for temperature

kelvin

solute

dissolved substance in a liquid

solvent

liquid

reference material

primary standard is a highly purified chemical that can be measured directly to produce a substance of exact known concentration and purity

National Institute of Standards and Technology (NIST)

certified standard reference material (SRMs) used instead of ACS standard

colligative properties

related to the # of solute particles per solvent molecules, not on the type of particles present

osmotic pressure, vapor pressure, freezing point , boiling point

conductivity

is a measure of how electricity passes through a solution

* depends on the # of respective charges of the ions present

resistivity

the reciprocal of conductivity, measure of a substance resistance to the passage of electrical current

* indicates and assesses the purity of water

most common used temperature unit used in the lab

Celsius and kelvin

TD (to deliver) pipettes

delivers the volume indicated to container, tip volume is not delivered

TC (to contain) pipettes

does not deliver the volume indicated to container, small amount of liquid is contained in pipette

mean

sum of terms divided by the number of terms

mode

value or a number that appears the most frequently in a data set

median

the middle value of a data set

standard deviation

the square root of the sum of squared differences from the mean divided by the size of the data set

spectrophotometry

measure the light transmitted by a solution to determine the concentration of the light-absorbing substances in the solution

beer law

relationship of absorption of light by a solution and the concentration of the solution

* \[ \] of a substance in directly proportional to the amount of light absorbed or inversely proportional to the logarithm of transmitted light

what is the most sensitive detector for spectrophotometry

photomultiplier

which of following correctly ranks electromagnetic radiation from low energy to high energy

microwaves, infrared, visible, UV, x-rays, gamma, cosmic

atomic absorption spectrophotometer

measure concentration by detecting radiation absorption by atoms not molecules

* hollow-cathode lamp
* precise accurate, sensitive and specific
* precise accurate sensitive and specific
* measure concentration of trace metals that are not easily sensitivity
* ICP with MS detection is the most sensitive and specific assay technique for all elements on the periodic chart

which instrumentation technique had the highest potential sensitivity

inductively coupled plasma (ICP) with MS detection

electroendosmosis

movement of buffer ions and solvent relative to the fixed support

* media, such as paper, cellulose acetate and agar gel take on a negative charge from adsorption of hydroxyl ions


* hydroxyl ions remains fixed while the free positives ions move toward the cathode
* ions are highly hydrated, resulting in net cathodic movement of solvent

osmometry

measure the concentration of solute particles in a solution

* colligative properties can change in number of dissolved particles

freezing point osmometer

impurities in solvent lower freezing or melting temp by reducing the bonding forces between solvent molecules causing molecules to exists as a fluid at lower temp

* decrease (depression) in the freezing point temp is proportional to the number of dissolved (solute) particles present