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 Intradermal injections 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 RAST 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