Module 7: Point of care testing and Lab procedures

Who staffs clinical laboratories?

Medical technologists, medical laboratory techs, laboratory assistants, medical assistants

What contributes to lab error more than any other factor?

incorrect specimen labeling

Specimen labeling technique

Label with patient’s name, DOB, date, time of collection, and MA’s initials

label container of specimen not lid (lid can be put on another by mistake)

laboratory requisition form

patient demographic info, providers signature, specific tests, source of specimen, date and time of collection, diagnosis code

can be electronic or on paper

Urinalysis

physical, chemical, microscopic examination of urine

Hematology

blood cell counts that determine RBCs, WBCs, and platelets of blood specimen

Chemistry

chemicals found in blood, CBF, urine, joint fluid, lipid profile (triglycerides, cholesterol (HDL, LDL) fasting glucose

Microbiology

studying bacteria, fungi, parasites, yeasts, and viruses in specimen

specimen include urine, blood, sputum, CBF, Stool, wound material

Cytology

microscope examination of cells for diagnostic purposes

blood bank

processes and stores blood and blood products for transfusion and blood disorder treatments

Pregnancy testing

Urine is screened for hCG antibodies

urine sample is obtained

Rapid strep test

throat swabs are obtained to screen for group A strep

both sides of posterior throat and tonsil area are swabbed and tested for presence of group A antigen

urianalysis

screening tool for analytes that are excreted in urine

Hemoglobin

capillary blood from fingerstick to screen for hemoglobin

spun hematocrit

fingerstick collection of blood taken in microcapillary tubes

centrifuged and evaluated for % of RBCs

Blood glucose

whole blood analyzed in glucometer to test for diabetes (capillary blood from fingerstick)

Hemoglobin A1C

capillary blood test determines control over blood glucose over 3 month period

Cholesterol testing

lipids evaluated from capillary blood sample

Helicobacter pylori

whole blood sample test for H. pylori antibodies

Mononucleosis screening

screening tool to test for presence of Epstein-Barr virus in capillary sample

Nasopharyngeal swab for Influenza type A & B

test for influenza antigens using swab into nostril

Drug testing

detected in urine sample

Fecal occult blood

screen for hidden blood in the stool

what kind of tests do ambulatory care centers typically perform?

CLIIA waved testing and perform per provider’s request

CLIA waived testing

most common designation for ambulatory care and lowest level of complexity

could be easily performed in home environment or medical office with minimal risk of incorrect results

no reasonable harm to patient if tests are performed incorrectly

Nonwaived tests

high complexity tests that require lab to have CLIA certificate and undergo inspections

view specimens microcopically

this is moderate testing but CLIA approves provider performed microscopy procedures

Quality assurance

comprehensive and relates to policies and procedures that must be implemented for reliability of test results

Quality control

included in quality assurance but is more specific

related to test reliability and accuracy while attempting to uncover errors and eliminate them

Specimen collection requirements

collect specimen at right time

collect specimen from site of suspected infection

minimize transport time to reference lab

collect the appropriate quantity

use appropriate containers and label them accordingly

Random urine sample

this sample can be collected at any time of the day and is used for screening purposes, the patient urinates into clean nonsterile container

First morning specimen

the patient collects their first urine specimen of the morning

this is more concentrated and is used for pregnancy testing or when proteins/nitrites need to be evaluated

Clean catch midstream

patient cleans with three moist antiseptic wipes

patient begins urinating

then put cup in stream and collect up to line

24 hour sample

large container with preservatives

patient discards first sample and collects all remaining urination specimens for next 24 hours

important in analysis of components like protein or kidney function

Catheterized collection

used when sterile urine sample is needed or if patients can’t provide sample on their own

specimen processing

some specimens might need to be processed prior to transport to maintain integrity of specimen

Urine sample timing

must be tested in 1 hour of collection, and if not specimen should be refrigerated

if it is left out then it can cause bacteria to grow

Chain of custody

specimen must be placed in a bag that is permanently sealed until opened for analysis

seal will ensure that there is no tampering with bag’s contents

What does an office without a lab interface have to do?

they must scan or upload their results to the electronic health record system

Normal values for Hemoglobin (HGB)

Male: 14 - 18 g/dL

Female: 12-16 g/dL

Hematocrit (HCT)

Male: 42-50%

Female: 37-47%

Complete Blood Count (CBC)

WBC: 4,000-11,000 / m³

RBC: 4.2-5.9 million/µL

Platelet count: 150,000 - 450,000/ mm³

Granulocyte ratio: 50-70% (of all WBC)

MCV: value score of 90-98 fL

Glucose

70-99 mg/dL (fasting)

Hemoglobin A1C

4-5.6%

Total cholesterol

less than 200 mg/dL

Cholesterol (LDL)

less than 100 mg/dL

Cholesterol (HDL)

Male: greater than 40 mg/dL

Female: greater than 50 mg/dL

triglycerides

less than 150 mg/dL

Preanalytical phase

provider orders a test to screen/monitor/diagnose a condition

written or electronic requestion is filled out

specimen is collected, labeled, and processed

specimen is transported to laboratory of prepared for offsite laboratory pickup

Preanalytical errors

inappropriate test request

order entry error

misidentification of patient

inappropriate container

improperly labeling of specimen

inadequate sample collection

inadequate sample/anticoagulation ratio

Analytic phase

instruments are maintained and calibrated

controls are run and analyzed for each testing method

specimen is tested and results are compared with expected values

tests are logged and documented in health record

Errors for analytical phase

equipment malfunctions

sample mixup

unindicated failure of quality controls

procedures not properly followed

post analytical phase

specimen discarded

analysis of control results compared over time

patient reports are logged

provider interprets and signs all lab reports

patient is notified of results

final report is documented in patient’s health record

postanalytical errors

failure to report

improper data entry

excessive turnaround time

Vision test distance

adults: 20 feet

children: 10 feet

Vision accuity chart

Snellen chart

vision fraction

numerator: distance at which test is performed (20 feet)

denominator: distance at which patients with typical vision can read the line

Near vision screening distance

14-16 inches away from the eyes

Color vision testing

Ishihara test

if patient misses 4+ plates then warrants further testing

Tympanometry

movement of tympanic membrane

earbud detects eardrum movement

test determines possible fluid or potential infections in middle ear

What does normal tympanogram look like?

produces peak on graph

What does abnormal tympanogram look like?

produces flat line

Normal range for hearing

adult: tones below 25 decibels

child: tones below 15 decibels

Intradermal allergy test

conducted on forearm or upper back

if wheal occurs in 15 mins might be possible allergen

the larger the wheal the more significant the allergy

Prep for Spirometry/Pulmonary function tests

no large meals 2 hours before test

no smoking 1 hour before test

discontinue the use of bronchodilators (inhalers/nebulizers) for at least 6 hours prior

Spirometry/PFT technique

loose clothing sitting upright or standing

breathe through mouth pursing lips around mouthpiece (noseclip can be applied to ensure no nose breathing)

lift chin slightly and extend neck

take deepest breath possible and seal your lips around the mouthpiece

blow as hard and fast as you can, blowing until you empty the air from your lungs

repeated three times

Expected value of PFT: FEV1

80%-120%

Expected value of PFT: FVC

80%-120%

Expected value of PFT: absolute FEV1/FVC ratio

within 5% of predicted ratio

Expected value of PFT: TLC

80-120%

Expected value of PFT: FRC

75%-120%

Expected value of PFT: RV

75-120%