Module 3D: Point of Care Testing and Laboratory Procedures Flashcards
Clinical Laboratory Improvement Amendments (CLIA)
A 1988 amendment that regulates federal standards that apply to all clinical laboratory testing performed on humans in the United States.
Clinical laboratory testing
Testing used in conjunction with health history and physical examination to provide essential data for the diagnosis and management of a patient’s condition.
Clinical laboratories staff
- a director
- certified medical technologists (MTs)
- certified medical laboratory technicians (MLTs)
- medical laboratory assistants (MLAs)
- certified clinical medical assistants (CCMAs)
- phlebotomists
Information Required on Completed Requisition
- The first part of the requisition includes patient demographic information. If the requisition is computer-generated, this information should populate automatically.
- A provider’s signature or authentication that the provider ordered the lab work is also present on all requisitions.
- The specific tests ordered by the provider must be identified and marked. These are often organized on the laboratory requisition based on the clinical laboratory department that will perform the test.
- The source of the specimen, date and time of specimen collection, and diagnosis code related to the medical necessity of the test ordered, is also required on the requisition.
Departments in Clinical Laboratory
- Urinalysis
- Hematology
- Chemistry
- Microbiology
- Cytology
- Blood bank
Urinalysis test
Includes the physical, chemical, and microscopic examination of urine
Hematology tests
Study of cause, prognosis, treatment, and prevention of diseases related to blood.
Tests: Blood cell counts that determine RBCs, WBCs, and platelets of a blood specimen
Chemistry tests
Chemicals found in blood, cerebrospinal fluid, urine, joint fluid, lipid profiles (such as triglycerides, total cholesterol, HDL, and LDL), and fasting glucose
Cholesterol
A waxy, fatlike substance made by the liver.
Microbiology tests
Study of all living organisms that are too small to be visible by the naked eye.
Tests: Studying bacteria, fungi, parasites, yeasts, and viruses; specimens can include urine, blood, sputum, cerebrospinal fluid, stool, and wound material
Cytology test
Microscope examination of cells for diagnostic purposes
Blood bank
Processes and stores blood and blood products for transfusion and blood disorder treatments
What must be included on a specimen container label?
- patient’s name and date of birth
- date and time of collection
- medical assistant’s initials.
Point-of-Care Testing
Various tests related to chemistry, immunology, microbiology, and hematology are identified as CLIA-waived and easily performed in provider office laboratories.
Ex:
- Pregnancy testing
- Rapid Streptococcus Testing
- Dipstick, Tablet, or Multi-Stick Urinalysis
- Hemoglobin
- Spun Hematocrit
- Blood Glucose
- Hemoglobin A1C
- Cholesterol Testing
- Helicobacter Pylori
- Mononucleosis Screening
- Nasopharyngeal Swab Specimen for Influenza Types A and B
- Drug Testing
- Fecal Occult Blood
Rapid Streptococcus Testing
Throat swabs are obtained to screen for group A streptococcus.
Both sides of the posterior throat/tonsil area are swabbed and tested for the presence of the group A antigen.
Analytes
A substance or chemical that is being identified and measured.
Pregnancy Testing
Urine or blood is screened for the presence of human chorionic gonadotropin (hCG) antibodies.
hCG: Hormone secreted by the placenta during pregnancy.
For the purpose of point-of-care testing, a urine sample is obtained to evaluate for the presence of hCG.
Urinalysis
Dipstick, Tablet, or Multi-Stick Urinalysis
The urinalysis is a screening tool for analytes that are excreted in the urine.
The urine sample is performed and tested with a reagent strip.
Hemoglobin Test
A machine is used to screen for the oxygen-carrying protein in whole blood, performed using capillary blood from a fingerstick (capillary puncture).
Specimen Type:
- Hematology
- Blood specimen
Spun Hematocrit Test
Fingerstick (capillary puncture) collection of blood is obtained in microcapillary tubes, which are centrifuged and evaluated for the percentage of red blood cells.
Specimen Type:
- Hematology
- Blood specimen
Blood Glucose Test
Whole blood is analyzed in a glucometer for a quantitative glucose level and is a screening test for diabetes, performed using capillary blood from a fingerstick.
Specimen Type:
- Chemistry
- Blood specimen
Quantitative
Related to measuring the amount of something.
Hemoglobin A1C Test
This capillary blood test determines the approximate control of blood glucose levels over a 3-month period.
Specimen Type:
- Hematology
- Blood
Cholesterol Testing
Lipids are evaluated from a capillary blood sample.
The sample is placed on a reagent strip and analyzed in a cholesterol testing machine.
Specimen Type:
- Chemistry
- Blood
Helicobacter Pylori Test
A whole blood sample can screen for the presence of H. pylori antibodies.
Helicobacter PylorI
Type of bacteria that infects the digestive tract.
Mononucleosis Screening
This screening tool tests for the presence of the Epstein-Barr virus in a capillary blood sample.
Mononucleosis
Contagious virus that is spread through saliva, also known as mono, most commonly caused by the Epstein-Barr virus.
Nasopharyngeal Swab Specimen for Influenza Types A and B
This screening is a qualitative test for multiple influenza antigens using a swab that is inserted into the nostril to obtain the sample specimen.
Qualitative
Identifying or measuring by the quality of something rather than its quantity.
Drug Testing
Substances such as recreational drugs and medications can be detected in urine and blood samples.
*These are considered legal specimens because they may be used in a court of law and must be handled carefully.
- The specimen has to be placed into a specimen bag that is permanently sealed until it is opened for analysis.
- The seal will ensure that there has been no tampering with the bag’s contents prior to reaching the lab for testing.
Fecal Occult Blood
This test is performed to screen for hidden blood in the stool. This test is performed with a fecal occult blood testing kit using the patient’s stool specimen.
CLIA-Waived Testing
Ambulatory care centers typically perform CLIA-waived testing, which is the simplest form of testing of all laboratory procedures.
- These tests could be performed in the home environment or easily conducted in the medical office with minimal risk of incorrect results.
- They pose no reasonable risk of harm to the patient if the tests are performed incorrectly.
CLIA-NONWaived Testing
Moderate- and high-complexity tests are considered nonwaived.
- Labs performing these tests must have a CLIA certificate and undergo inspections to ensure standards are being met.
- These tests are typically performed in a reference or hospital laboratory.
Quality control (QC)
Action is performed to ensure the reliability of test results by detecting and eliminating error.
Quality assurance (QA)
Comprehensive and relates to policies and procedures that must be implemented for the reliability of test results.
Maintenance of a desired level of quality related to a service or piece of equipment.
Quality control vs Quality assurance
Quality control (QC) is included in quality assurance but is more specific; it is related to test reliability and accuracy while attempting to uncover errors and eliminate them.
Ex:
- reviewing the expiration date of urine reagent strips is a means of quality control, whereas policies related to rotating stock to put the newest containers in the back of the storage area is a quality assurance measure.
- checking the temperature of the laboratory refrigerator and documenting it on a log is a quality control measure. The policy of checking the temperature and maintaining it between 2° C and 8° C (35° F and 46° F) is a quality assurance measure.
Specimen Collection Techniques and Requirements
- Collect the specimen at the appropriate time.
- Collect the specimen from the site of suspected infection.
- Minimize transport time to a reference lab.
- Collect the appropriate quantity.
- Use the appropriate containers and label them accordingly.
Urine Specimens
Urine is the most commonly tested specimen in an ambulatory care setting.
There are various means of collecting urine specimens:
- Random Urine
- First Morning Specimen
- Clean-Catch Midstream
- 24-Hour Sample
- Catheterized Collection
Random Urine Sample
This sample can be collected at any time of the day and is used for screening purposes. The patient urinates in a clean, nonsterile container.
First Morning Urine Specimen
The patient collects their first urine specimen of the morning in a clean container.
This specimen is more concentrated and is often used for pregnancy testing or when other analytes (protein, nitrites) need to be evaluated.
Clean-Catch Midstream Urine Sample
This specimen is used for cultures or when a noncontaminated specimen is required.
- The patient cleanses the genitalia area using three moist antiseptic wipes.
- Females will cleanse each side and the middle of the urinary meatus from front to back using a separate wipe for each passage. (total of 3 wipes)
- Males will cleanse each side of the glans penis and across the middle using a separate wipe for each passage. - The patient will begin by urinating in the toilet, then pause and collect the rest of the urine specimen in a sterile container or until it is adequately filled.
24-Hour Urine Sample
This type of collection is important in the quantitative analysis of components such as protein when analyzing kidney function.
It is also used to analyze substances that are sporadically released into the urine over a 24-hour period.
This method uses a large container with preservatives:
- The patient discards their first morning urine specimen and collects all remaining urination specimens for the next 24 hr, including the first morning void of the second day.
Catheterized Collection
This method is used when a sterile urine sample is needed or if patients are unable to provide a specimen on their own.
It involves insertion of a sterile tube (catheter) through the urethra into the bladder.
- The provider or nurse performs this procedure, with the medical assistant prepping the patient and assisting, if needed.
Collection of Stool Specimens
A fecal occult blood test requires a stool specimen collection to screen for the presence of hidden blood, which can indicate the presence of disease or gastrointestinal bleeding.
Correct patient instructions are imperative to ensure that false positives do not occur:
- Instruct the patient on medications and foods to avoid for three days prior to obtaining the specimen
- Patients should avoid red meats or dyes, aspirin or aspirin products, vitamin C, and iron supplements because these could create false-positive fecal occult blood tests (FOBT).
Collecting Specimens for Cultures
Specimens for cultures are always collected in sterile containers.
- Take precautions to avoid touching the insides of lids, swabs, or containers, which could contaminate the specimen.
If the specimen is not properly collected, the identification of the causative agent might not occur, and proper treatment cannot be started.
Examples of patient identifiers
- Name
- Assigned identification number (e.g., medical record number)
- Date of birth
- Phone number
- Address
Appropriate packaging for specimen transport
Each (individual) specimen must have a clear plastic bag with a zip closure and dual pockets, which allows for the separation of the specimen and lab requisition. The requisition form should be placed in the outside pocket of the bag.
Whenever specimens are transported via mail, biohazard identification on the outside of the package alerts handlers of a potentially infectious agent within the package.
*If the container has the potential to break or crack, padding and protection from leakage must occur.
- Wrapping the container in absorbent material and placing the item in a biohazard bag are added safety measures to ensure that the outside of the package does not get contaminated.
Chain of custody
A chain of custody must be established to document the handling of the specimen.
Everyone who handles the specimen, including the patient being tested, must sign the chain of custody form.
The chain of custody form will indicate the source of the specimen.
The patient’s signature on the consent form states, officially, that they are the same person that provided the sealed specimen to send for laboratory analysis.
Appropriate packaging for drug and alcohol analysis specimen transport
These are considered legal specimens because they may be used in a court of law and must be handled carefully.
- The specimen has to be placed into a specimen bag that is permanently sealed until it is opened for analysis.
- The seal will ensure that there has been no tampering with the bag’s contents prior to reaching the lab for testing.
Special handling for urine specimens testing for bilirubin
Always follow proper office procedure and reference the lab manual for proper handling of specimens.
A urine sample that requires testing for bilirubin needs special handling to protect the specimen from light, which would affect the accuracy of the testing. For this situation, a dark container is required for the specimen.
Time and storage requirements for urine samples
Urine samples also need to be tested within one hour of collection, and if not tested, the specimen must be refrigerated.
When urine is left sitting out longer than an hour, it can allow bacteria to grow and cause the test to have inaccurate results. Refrigerating helps prevent the bacteria from growing.
Hemoglobin (HGB)
Iron-containing oxygen-transport in red blood cells that is responsible for carrying oxygen from the respiratory organs to the rest of the body.
Hematocrit (HCT)
Volume percentage of red blood cells in blood.
Critical value
Laboratory results at such variance to the normal value range that a potentially life-threatening, pathophysiologic state is occurring. Action must be taken as soon as possible.
Hemoglobin (HGB) Reference Range/Results
Male: 13.5 to 17.5 g/dL
Female: 12 to 16 g/dL
Hematocrit (HCT) Reference Range/Results
Male: 41% to 53%
Female: 36% to 46%
Complete Blood Count (CBC) Reference Range/Results
White blood cell count: 4,500 to 11,000/mm3
Red blood cell count:
- Male: 4.5 to 5.9 million/mm3
- Female: 4 to 5.5 million/mm3
Platelet count: 150,000 to 400,000/mm3
Granulocyte ratio: 50% to 70% (of all white blood cells)
Hemoglobin (Hgb):
- Male: 13.5 to 17.5 g/dL
- Female: 12 to 16 g/dL
Hematocrit (Hct):
- Male: 41% to 53%
- Female: 36% to 46%
Mean corpuscular volume (MCV): A value score of 80 to 95
Glucose Reference Range/Results
70 to 100 mg/dL (fasting)
Hemoglobin A1C Reference Range/Results
Below 5.7%
Cholesterol Panel/Lipid Profile Tests and Reference Range/Results
Total Cholesterol: 130 to 200 mg/dL
Low-density lipoprotein (LDL): Less than 100 mg/dL
High-density lipoprotein (HDL): Greater than 60 mg/dL
Triglycerides: 40 to 150 mg/dL
Complete Blood Count (CBC) Tests
A blood test that measures the number and types of cells in your blood to assess your overall health.
A CBC can help diagnose and monitor a variety of conditions, including: anemia, infection, leukemia, inflammation, blood disorders, and bone marrow and spleen function.
Specimen type:
- Hematology
- Blood specimen
Tests Included:
- White blood cell count
- Red blood cell count
- Platelet count
- Granulocyte ratio
- Hemoglobin (Hgb)
- Hematocrit (Hct)
- MCV
Mean corpuscular volume (MCV)
Blood test measures the average size of red blood cells. Part of a complete blood count (CBC)
Common Testing Errors
- Mislabeled specimens
- Improper instructions for clean-catch urine samples: This could alter the results of the test due to excessive bacteria presence and may result in the need for the patient to provide a new sample.
- Lack of patient adherence: A patient who has not completed proper testing preparation may need to delay their testing, such as when a patient has not fasted for bloodwork requiring fasting.
Preanalytical Phase Errors
Errors That Affect the Results:
- Inappropriate test request
- Order entry error
- Misidentification of the patient
- Inappropriate container
- Improperly labeling of specimen
- Inadequate sample collection
- Inadequate sample/anticoagulation ratio
Preanalytical Phase
- The provider orders a test to screen, monitor, or diagnose a patient’s condition.
- A written or electronic requestion is filled out, showing the requested tests to be ordered, the specimen required, and where the specimen will be tested.
- The specimen is collected, labeled, and processed.
- The specimen is transported to the laboratory or properly prepared for offsite laboratory pickup.
Analytic Phase
- Instruments are maintained and calibrated.
- Controls are run and analyzed for each testing method.
- The specimen is tested, and the results are compared with reference ranges.
- The test results are logged and documented in the patient’s health record.
Analytic Phase Errors
Errors That Affect the Results:
- Equipment malfunctions (Personnel are required to perform calibration on laboratory equipment.
- Preventive maintenance schedules must be followed and documented.)
- Sample mix-up
- Unindicated failure of quality controls
- Procedures not properly followed
Postanalytical Phase
- Specimens are properly discarded.
- Analyses of control results are compared over time.
- Patient reports from outside laboratories are logged or documented.
- The provider interprets and signs all lab reports.
- The patient is notified of the results in the office or is contacted by laboratory personnel.
- The final report and all communication with the patient are documented in the patient’s health record.
Postanalytical Phase Errors
Errors That Affect the Results:
- Failure to report
- Improper data entry (Accurate recording is a key responsibility of the medical assistant.)
- Excessive turnaround time
3 stages required for quality assurance in the laboratory
- Preanalytical Phase
- Analytic Phase
- Postanalytical Phase
These three stages must be applied to each test or procedure that is performed in the laboratory.
*If any of these steps are missed or not performed correctly, quality assurance is broken.
Specialty Testing
Tests performed in the medical office that do not fall under point-of-care testing or CLIA-waived tests are considered specialty tests.
Ex:
- hearing and vision screening tests
- respiratory or peak flow testing
- allergy testing
*Specialty exams and procedures vary based on the provider and the medical specialty in which they practice.
Vision Testing
Performed as a noninvasive screening to detect visual abnormalities of the eye.
- Distance vision is easily tested by using a Snellen chart to evaluate for myopia (nearsightedness).
- Near vision testing screens for presbyopia (a refractive disorder that occurs with the aging eye) or hyperopia (farsightedness) by using the Jaeger eye chart.
Distance Vision Testing
Each eye is tested individually, and then both are tested together.
- Adult patients stand 20 feet and identify letters on the Snellen chart, with each row of letters getting progressively smaller in size.
- Children stand 10 feet away from a chart at eye level and identify letters, shapes, or the direction an “E” is pointing.
*Patients are allowed to wear corrective lenses during the test (which should be documented in the patient’s EHR).
Result:
- The last line at which the patient can clearly read the letters or pictures with accuracy is their screening result.
- Most facilities state that a patient can miss one item and still pass that line. Once the patient misses two items in a single line, the test is complete, using the previous line read without error as the final result.
Vision testing results
Vision is recorded as a fraction.
- The numerator in the fraction represents the distance at which the test is performed (20 feet away from the chart).
- The denominator represents the distance at which patients with typical vision can read the line.
Ex: a patient with 20/20 vision represents typical vision.
Near Vision Testing
Using the Jaeger eye chart, the patient is asked to read words from various-sized prints on cards that are held 14 to 16 inches away from the eyes (*without corrective lenses).
Each eye is tested individually, and then both are tested together.
Result:
- The level at which the patient can read the smallest printing clearly and accurately is the final result.
Ishihara test
Vision test to assess for color deficiency. The most common type of color deficiency is a red-green deficiency.
Procedure:
- Screening is done by testing the patient using 11 color plates within an Ishihara test color-plate book.
- If the patient misses four or more plates, there might be a color deficiency, and further testing is warranted.
Hearing Tests Performed in Ambulatory Care
Hearing screenings can be a valuable tool in detecting hearing loss.
These tests use an audiometer to measure hearing acuity at different frequencies:
- Tympanometry
- Speech, Tone, and Word Recognition Information
Sound amplitude is measured in decibels (dB), and sound frequency is measured in hertz (Hz).
Tympanometry
Records movement of the tympanic membrane, which can be affected by increased pressure in the middle ear.
Using a small earbud, eardrum movement can be measured by changing the amount of air pressure applied.
This test is valuable for determining the presence of fluid and potential infections in the middle ear.
A normal tympanogram produces a peak on the graph, whereas an abnormal tympanogram will produce a flat line.
Speech, Tone, and Word Recognition Information
Medical assistants can perform audiometry if patients (especially children) can respond to directions.
- The patient will wear a set of headphones, and various tones will be played.
- The patient will be directed to push a button or raise their hand to indicate they hear the tone.
The level of hearing is documented in decibels and the frequency in hertz.
An adult who has normal hearing should be able to hear tones below 25 decibels, and a child should be able to hear below 15 decibels.
Allergy Testing Patient Education
Instruct the patient to discontinue the use of antihistamines three days prior to allergy skin testing.
- Antihistamines block histamine’s response time, inhibiting skin testing reactions and possibly producing a false-negative result.
Scratch Test
A diluted allergen is applied to a scratch or prick that has been made on the surface of the patient’s skin.
- The testing is usually conducted on the forearm or upper back.
If a wheal occurs in the first 15 minutes, the allergist can identify the substance as a possible allergen and consider further allergy testing to be conducted intradermally.
*Generally, the larger the wheal, the more significant the allergy. If a wheal is evaluated less than 15 minutes from time of application, it may not have had enough time to develop a reaction.
Intradermal Allergy Testing
A diluted allergen is injected intradermally, and the patient is observed.
An initial wheal is expected. If the wheal becomes inflamed with induration (raised, hard area), the substance can be identified and confirmed as an allergen.
*Generally, the larger the wheal, the more significant the allergy. If a wheal is evaluated less than 15 minutes from time of application, it may not have had enough time to develop a reaction.
Spirometry
aka pulmonary function test, is a noninvasive test that detects the lung’s ability to function will help assist in the detection and evaluation of pulmonary disease.
It is an automated test that produces a graphic result by measuring how “fast” a patient can move air into and out of the lungs and how “much” air is moved into and out of the lungs.
Determining predicted respiratory values
The patient’s demographic factors (age, gender, weight, and height) are used to calculate the predicted respiratory values for a healthy patient.
These values are then compared to three measured values that are obtained while the patient is performing the test.
Pretest preparation for spirometry
This prep includes the following.
- No large meals 2 hours before the test
- No smoking 1 hour before the test
- Discontinuation of the use of bronchodilators or other breathing therapies (inhalers, nebulizers) for at least 6 hours before the test
Spirometry Procedure
- The patient should wear loose clothing, be in an upright sitting or standing position, and breathe through the mouth, pursing the lips around the mouthpiece.
- The medical assistant will likely apply a clip to the patient’s nose to avoid nose-breathing during the procedure.
- The patient should lift the chin slightly and extend the neck a little during the test to reduce breathing resistance.
- Instruct the patient to “Take the deepest breath possible. Seal your lips around the mouthpiece. Blow as hard and as fast as you can, blowing until you empty the air from your lungs.”
The procedure is repeated until there are three acceptable maneuvers or attempts.
*Proper coaching is essential for yielding the best results from the patient.
Expected Values of Pulmonary Function Tests
Expected Value (95% confidence interval)
FEV1: 80% to 120%
FVC: 80% to 120%
Absolute FEV1/FVC ratio: Within 5% of the predicted ratio
TLC: 80% to 120%
FRC: 75% to 120%
RV: 75% to 120%
Peak Flow Rates
This test can be used to monitor lung function at home by the patient. This is especially helpful for patients who have chronic respiratory diseases such as asthma or chronic obstructive pulmonary disease (COPD).
A peak flow rating of 80% or better is considered well-controlled and does not require treatment.
Peak flow meter
Device that measures the forced expiratory volume, which indicates the effectiveness of airflow out of the lungs.
Patient education for peak flow meters
- Wear nonrestrictive clothing.
- Begin with the marker at the bottom of the scale on the meter.
- In an upright sitting or standing position, take a deep breath and forcefully blow out of the mouth, which is secure around the mouthpiece of the machine.
- Record the number where the marker is located at the end of the test.
- Repeat the test two to three times and record the results.
