Section 2 - Quality Assurance and Quality Control

Preanalytical activities

refers to everything that affects a patient specimen before it is tested for the analyte

well-written procedures and polices

What can help minimize preanalytical errors?

examples of preanalytical activities

complete physical's order/requisition

patient identification

patient instructions or compliance

collection of specimen

labeling of specimen

processing of specimen

storage of specimen

transportation of specimen

avoid contamination

Analytical activities

refers to every step involved in the actual analysis of lab specimen

accuracy and precision

Using analytical methods with high degree of __________ and ________, as well as maintaining optimal operating conditions of instruments help to minimize analytical errorr

examples of analytical activities

specimen preparation

reagent preparation

instrument maintenance & calibration

quality control & proficiency testing

producing the lab report

Postanalytical activities

refers to those variables that affect patient results in the reporting stage

examples of postanalytical activities

positively identifying the test report with pt sample

reporting pt results in timely manner

using reporting format that can be understood/interpreted by health care providers (complete with reference ranges)

system for alerting health care providers with critically significant results

notifying health care providers when results arrive from outside reference labs

patient notification

proper disposal of lab specimen & other biohazardous lab supplies

disinfection/decontamination of work areas where testing takes place

Proficiency testing

external QC

measurement of unknown samples that are sent from an outside agency at set intervals, as a test of competency of the testing process

- analytical tesing

- 3x/yr w/ 5 challenges per analyte testing

80%

Labs must meet _____% of all PT challenges

**hint: 4/5 challenges passed

deemed status

The agency that provides samples for proficiency testing must have obtained _________ from the federal government (CLIA) in order to offer approved PT programs

CAP, AAB, AAFP, AABB

examples of agencies with deemed status

1st fail

PT Testing fail:

no formal report; repeat test 4 months later

2nd fail

PT Testing fail:

investigation -- written report

3rd fail

PT Testing fail:

investigation & probation

4th fail

PT Testing fail:

no longer allowed to run analyte test in lab

improvement of lab medicine

What is the goal of proficiency testing?

PT Report

a statistical report, which compares the testing lab with peer labs & is prepared by the PT agency

- report includes SDI and CV values

(lab result - peer mean) / peer SD

What is the equation to calculate SDI?

deterioration of accuracy

The PT Report

can be assessed by shifts and changes in the daily QC

caused by: calibration variances, method validation issues etc.

imprecision

The PT Report

demonstrated by an increase in the SD of QC results over time

caused by: differences in pipetting, noise in the electrical system, temp, or number of other factors

< 2

What is the acceptable SDI?

≥ 2

SDI score of _____ deserves some special concern, regardless what the test is

> 1

SDI score of _____ deserves some special attention because method shows a systematic difference from the group

in the future, this bias might lead to unacceptable results

SD x 100 / mean

What is the equation to calculate CV?

true

T or F:

The larger the concentration, the larger the standard deviation

10%

In general, a CV of _____% is acceptable

< 15%

For low level assays, what is an acceptable CV?

identifying sample errors

procedural factors (instrument, reagents, methods)

CV is useful to the lab in what ways? (2)

appropriate education for the task

training for the specific requirements of each test

experience in testing the specific test

What are the requirements for the competency evaluation of laboratory personnel? (3)

Standard Operating Procedure (SOP)

documentation of best practice and work instructions to use to perform a common lab task/test

Purpose: define requirements for each test

at hire

six months after hire

annually thereafter

Competency to perform tests must be demonstrated when? (3)

info included in SOP

specimen requirements

specimen handling & processing requirements

transportation & storage requirements

test methodology

linearity (reportable range info)

reference range info

dilution info

interference/limitations

Delta check

computerized check that is performed to detect changes form earlier individual patient test results

routinely checks patient results and falls when results are outside normal variation

may be reported in percent change/unit increments form the initial test results

misidentified specimens

Delta checks are particularly helpful in detecting:

ICD coding

diagnosis codes

set by WHO

CPT coding

codes assigned to every task and service a medical practitioner may provide to a patient including medical, surgical and diagnostic services

developed, maintained and copyrighted by the AMA & updated regularly

clerical error

What is one of the most common causes of error in lab testing?

diet

lab values are significantly affected by the ingestion of food

ex: glucose, insulin, lipid panels

basal state

the condition of the patient early in the morning

post-prandial state

condition of the patient after food

- usually duration is defined (2hrs, 4hrs, etc)

- not as common due to how hard it is to maintain consistency of meals

diurnal variations

blood constituents have normal fluctuations during a 24hr day

ex: increase of cortisol & testosterone in AM, decrease WBC & iron in AM

test affected by diurnal variation

iron

parathyroid hormone

prolactin

renin/aldosterone

TSH

ACTH

catecholamines

adrenal steroids

gastrin

growth hormone

glucose

exercise

increases many blood chemistries

ex: lactic acid, creatinine, protein, uric acid, CK, LDH

patient position

will cause plasma to tilter in the tissues

- causes a decrease in plasma volume and an increase in formed elements in blood

ambulatory vs sublime

ambulatory

pt is up and walking

sublime

pt is laying down

orthostatic proteinuria

decreased levels when sleeping

increased levels when up & moving

pregnancy

pt has their own established normal ranges

smoking

increases cortisol, WBC and hemoglobin

stress

high stress affects WBC counts, serum iron and increases adrenal hormone values

drugs

alters many physiological functions; numerous are toxic to the liver

can affect colorimetric assays and reagents binding reactions

ex: Diuretics, chemo, steroids

variations due to phlebotomy

prolonged tourniquet use

repeated fist clenching

out of order draw

hemolysis

lipemia/icterus

1 min

Tourniquets should only be left on for no longer than how long?

if left longer, hemoconcentration occurs due to fluid changes

below IV insertion

If you must draw from an arm involved in IV therapy, where do you draw?

fist clenching

should be avoided prior to collection

hemolyzes sample -- increases in lactate, phosphate, and potassium (due to spill out of RBCS)

decreases pH

blood culture, light blue, red/gold, green, purple, gray

What is the order of draw?

**hint: Be a Really Good Phlebotomist

use a discard tube before using light blue

When drawing with a butterfly tube, what should you do?

mild, moderate, gross

Hemolysis is graded based on the visible presence of hemoglobin; what are the levels?

gross hemolysis

Almost every test will be affected by what type of hemolysis?

due to interference with colorimetric testing, and release of intracellular constituents into the serum

true

T or F:

Grossly hemolyzed specimens should always be rejected

potassium

What test is the most affected by hemolysis?

**hint: 98% found intracellular & hemolysis releases it

Lipemia

the increased presence of triglycerides in the serum

causes a milky apperance

Icterus

the increased presence of bilirubin in the serum

causes a dark yellow coloration

serum

liquid part of blood that contains NO clotting factors

clot was formed

plasma

liquid part of blood that does contain clotting factors

NO clot was formed

Blue

Green

Purple

tubes where plasma is collected

Red

Tiger Top

Gold

tubes where serum is collected

clot activator; separation gel

Red

Red/Gray SST

Gold

What are the 3 common tubes used for chemistry testing?

Red top

no additive

- glass - no clot activator

- plastic - clot activator

Red/Gray SST top

clot activator and gel serum separator

Gold Top

may or may not have clot activator

has gel serum separator

advantages of gel tubes

less manipulation of specimen

minimize hemolysis over time

less chemical interaction of blood to serum

enhanced recovery of serum

decreased staff time

lower frequency of error with testing

storage time

disadvantages of gel tubes

Tests affected include:

TDM

RBC Enzymes

Lead

Trace Metals

Hormones

Renin

Catecholamines

Serum Separator Tube

What does SST stand for?

Plasma Separation Tube

What does PST stand for?

clot activator & no anticoagulant

Red Top/Tiger Top SST/Gold SST

What is the additive?

blood is allowed to clot prior to centrifugation

Red Top/Tiger Top SST/Gold SST

What is the mode of action?

chemistry

Red Top/Tiger Top SST/Gold SST

What is this tube used for?

Sodium heparin, Lithium heparin, Ammonia heparin

Green Tube / PST

What is the additive?

thrombin and thromboplastin

Green Tube / PST

Mode of Action: What does the anticoagulant (heparin) inhibit?

chemistry

Green Tube / PST

What is this tube used for?

Sodium fluoride and potassium oxalate

Light Gray Tube

What is the additive?

antiglycolytic

Light Gray Tube

prevents RBCs from breaking down and utilizing glucose

Sodium fluoride

5 days

Light Gray Tube

Mode of Action: The antiglycolytic agent (Sodium fluoride) preserves glucose for how many days?

glucoses

Light Gray Tube

What is this tube used for?

requires full draw

Sodium EDTA

Dark Blue / Royal Blue Tube

What is the additive?

forms calcium salts

Dark Blue / Royal Blue Tube

What is the mode of action?

trace element testing and toxicology

Dark Blue / Royal Blue Tube

What is this tube used for?

- acid wash to remove any contaminants from environment

2 hours

amount of time where serum/plasma should be separated by centrifugation

10-15 min

amount of time serum should be left to sit prior to centrifugation

premature centrifugation will permit continued formation of fibrin (leads to clots)

specimen handling and storage

should be tested within 4 hours or stored, refrigerated or frozen

blood should not be exposed to air for extended periods of time

should be protected from light as needed

4 hours

amount of time where serum/plasma needs to be tested or stored

refrigiration

storage of serum/plasma

maintains stability in the plasma and serum specimen

4C

Ammonia, blood gas, fluids for pH, lactate & pyruvate specimens should be stored at what temperature?

bilirubin and liver assays

affected by UV light -- use a dark-colored tube to keep exposure to light minimal

first morning urine

most ideal because of concentrated amounts

also timed collection reduce error from diurnal variations

Formalin

Thymol

Toluene

Urine preservative that reduces bacterial growth

Boric acid

HCl

Urine preservative that maintains the pH of urine and prevent changes in the concentration of urinary analytes

quality control

monitors the analytical aspect of a method, verifying that results from a given method are precise and accurate