7

Foundations of Nursing NUR 212

Diagnostic tests and specimen collection

Introduction

Diagnostic and laboratory tests occur in many environments. The traditional sites include hospitals , clinics , and the primary health care provider’s offi ce .

Diagnostic testing involves three phases : pretest , intratest , and post test

Roles of the Nurse in three phases of diagnostic test

I-In pretest phase :The major focus of the pretest

phase is the client’s preparation:

1-Prior to radiological studies , the nurse asks the client if pregnancy is possible , special precautions should be necessary .

2- The nurse also needs to know what equipment s and supplies are needed.

Roles of the nurse in the pretest phase

3- The nurse should know the answers of the following questions :

A-What type of sample will be needed and how it will be collected ?

B- Does the client need to stop oral intake for number of hours prior to the test ?

C-Does the test include administration of dye ?

D- Are fluids restricted or forced ?

E- How long is the test ?

F- Are medications given or withheld ?

Role of the nurse intratest

This phase focuses on specimen collection

- The nurse uses standard precautions and sterile technique as appropriate.

- During the procedure , the nurse provides emotional & physical support.

- The nurse ensures correct labeling .

- The nurse also ensures proper transportation of the sample to avoid invalid test results.

Role of the nurse in post-test phase

The focus of this phase is on nursing care of the client and follow up activities and observations.

- As appropriate , the nurse compares the previous and current test results and modifies nursing intervention as needed .

- The nurse also reports the results to appropriate health team member .

Nursing Diagnosis

Nursing Diagnosis includes :

1- Anxiety or fear R/T possible diagnosis of acute or chronic illness .

2-Impaired physical mobility R/T prescribed and restricted movement of involved extremity after testing .

3- Deficient knowledge R/T misperception received from others regarding processes for testing

A- Blood tests

Blood tests are one of the most commonly used diagnostic tests and can provide valuable information about the hematologic system and many other body system :

1-Complete Blood Count (CBC):

Specimen of venous blood are taken for a complete blood count , which include hemoglobin and hematocrit measurements , erythrocyte (RBC),leukocytes and differential white blood cell count .

2-Serum Electrolytes

Serum electrolytes are often routinely ordered for any client admitted to a hospital as a screening test for electrolyte and acid – base balance .Serum electrolytes also are routinely assessed for clients at risk in the community , for example clients who are being treated with diuretic for hypertension or heart failure .The most commonly ordered serum tests are for sodium , potassium , chloride , and bicarbonate .

3- Serum Osmolality Serum Osmolality is a measure of

the solute concentration of the blood . The particles include are serum ions , glucose and urea . Serum osmolality can be estimated by doubling the serum sodium , because sodium and its associated chloride ions are the major determinants of serum osmolality .Serum osmolality values are used primarily to evaluate fluid balance .Normal values are 280 to 300 mOsm/kg.An increase in serum osmolality indicate a fluid volume deficit , a decrease reflects a fluid volume excess .

4- Arterial Blood Gases

Measurement of arterial blood gases is another important diagnostic procedure . Specialty nurses , medical technicians and respiratory therapists normally take specimens of arterial blood from the radial , brachial or femoral arteries .

5-Blood Chemistry

A number of other tests may be performed on blood serum (in the liquid portions of the blood ) These are often referred to as blood chemistry .In addition to serum electrolytes , common chemistry examination include determining certain enzymes that may be present(including Lactate dehydrogenase , Creatine Kinase , Serum glucose , hormones as thyroid hormone and other substances as cholesterol and triglycerides.

6- Metabolic Screening

Newborns are routinely screened for congenital metabolic conditions .Tests for phenylketonurea and congenital hypothyroidism are required . Other conditions that are frequently screened involves collecting peripheral venous blood .

Discovered abnormalities allow health care providers and parents to plan early care .

7-Capillary Blood Glucose

A Capillary blood specimen is often taken to measure blood glucose when frequent tests are required or when a venipuncture cannot be performed .Hence , clients can perform this technique on themselves

B- Stool Specimens

Purposes of stool examination :

1- To determine the presence of Occult ( hidden ) blood .

2- To analyze for dietary products and digestive secretions .

3- To detect the presence of ova and parasites .

4- To detect the presence of bacteria or viruses.

Instructions of stool collection

1- Defecate in a clean bedpan or bedside commode .

2- If possible , do not contaminate the specimen with urine or menstrual blood . Void before the specimen collection .

3- Don’t place toilet tissue in the bedpan after defecation .Contents of the paper can affect the laboratory analysis.

4- Notify for specimen that need to be sent to the laboratory immediately

C-Urine Specimens

Urine is collected for the following :

1- Clean voided specimen

2- Clean –Catch or Midstream Specimen

3- Time Urine Specimen

1-Clean Voided Urine Specimen

Clean voided specimen is usually adequate for routine examination . Many clients are able to collect a clean voided specimen and provide the specimen independently with minimal instruction .

Routine urine examination is usually done on the first voided specimen in the morning because it tends to have a higher , more uniform concentration and a more acidic pHthan specimen later in the day

2- Clean –Catch or Midstream Specimen

Clean- Catch or Midstream voided specimens are collected when a urine culture is ordered to identify micro-organism causing urinary tract infection .

Clean – Catch specimen is collected in into a sterile specimen container with a lid .

3- Timed Urine Specimen

Some urine examinations require collection of all urine products and voided over a specific period of time , ranging from 1 to 2 hours to 24 hours.

Each voiding of urine is collected in a small , clean container and then emptied immediately into a large container.

D-Throat Culture

A throat culture sample is collected from the mucosa of the oropharynx and tonsillar regions using a culture swab . The sample is then cultured and examined for the presence of disease producing micro-organism