Copyright ©2012 Delmar, Cengage Learning. All rights reserved. Chapter 45 Diagnostic Testing

Copyright ©2012 Delmar, Cengage Learning. All rights reserved.

Chapter 45

Diagnostic Testing


Quality Control

• Quality control and assurance are important to the integrity of test results

• Perform controls:– At the beginning of each day– When opening a new bottle of reagent strips


Quality Control

• Document the following in the log book:– Date– Patient’s name– Test performed– Results of test– Your initials– Kit, reagent strip, lot numbers, expiration dates– Quality control results


Hematology Testing

• Hemoglobin and hematocrit– Screening tests that require a small amount of

blood– Usually obtained through a capillary puncture– Hematocrit may use either capillary blood or

venous blood


Hemoglobin

• Hemoglobin is essential to oxygen circulation in the body

• Normal ranges– Males: 14-18 g/dL– Females: 12-16 g/dL


Hematocrit

• Screens for anemia• Normal ranges

– Males: 40-54%– Females: 37-47%


Complete Blood Count

• Common test ordered in provider’s office, which measures many values

Total red blood cell count Total granulocyte count

Total white blood cell count Total lymphocyte and monocyte count

Total platelet count Percentage of granulocytes

Hemoglobin Percentage of lymphocytes and monocytes

Hematocrit Red blood cell indices


WBC Differential

• Performed on 100 white blood cells– Numbers of neutrophils, eosinophils, basophils,

monocytes, and lymphocytes counted• Physicians review for abnormalities of the red

blood cells• MAs do not perform these counts, but should

be familiar with the reports


ESR

• Rate at which red blood cells settle in a calibrated tube within a given time

• Determines how much inflammation is occurring in response to another disease condition

• Two methods– Westergren– Wintrobe


Glucose Testing

• Capillary blood samples usually used• Handheld meter with reagent strips• Perform quality controls

– At the beginning of each day– When opening a new package of reagent strips– Log results prior to reporting patient results


Glucose Tolerance Testing

• Performed when patient has consistently high fasting blood sugar– To help provider make a diagnosis of diabetes

mellitus or hypoglycemia• Determines the patient’s ability to metabolize

a glucose load over a prescribed amount of time


Hemoglobin A1C

• Modified form of hemoglobin• Helps determine how the diabetic patient has

been controlling blood sugar over 2-3 months• Often ordered with random blood sugar level


Immunology

• The study of the body’s ability to prevent and fight off infection

• Immunoassays are diagnostic tests that measure the amount of antigens and antibodies present relative to an illness


Mononucleosis Testing

• Illness causes by the Epstein Barr virus– Symptoms similar to the flu– Extremely contagious– Most common in individuals 10-25 years old

• Immunoassay detects the presence or absence of the antibodies to EBV


Allergy Testing

• This type of testing involves introducing an antigen directly into the patient’s skin to induce a reaction

• If the reaction is negative (normal), there will be no change in the skin

• If the reaction is positive, a wheal will develop on the skin


Allergy Testing

• Skin prick tests– Allergen is applied directly to patient’s skin and

scratched or “pricked” into the epidermis• Intradermal injections

– Allergen is injected between the epidermis and dermis


Allergy Testing

• Skin patch tests– Allergen-soaked pad is applied to the surface of

the skin for 24-72 hours• RAST

– Determines the presence of immunoglobulins– Test given when individuals cannot tolerate skin

tests


Allergy Testing

• Nasal smears– Aids in the diagnosis of allergies– Smear done with nasal secretions– Provider observes the eosinophil count


HIV Testing

• Standard screening tests are enzyme immunoassays

• May have to draw blood for this screening• Follow policy and procedure for collection as

well as standard precautions


PKU Testing

• Screening test done on infants using capillary blood– Drops of blood are soaked through outlined circles

on PKU testing card and attached to requisition– The card and form are send to state health

department for processing• Required in all states and Canada


Testing Outside the POL

• Series of tests ordered are done as panels or profiles– Panels are less expensive than individual tests

• MA responsibilities– Prepare specimen for sending– Screen test results as they are returned to

provider’s office– Immediately follow-up panic values

Documents

Copyright ©2012 Delmar, Cengage Learning. All rights reserved. Chapter 45 Diagnostic Testing