Laboratory and Drug Testing

Labs and Diagnostic Studies

objective measurements to complement clinical assessments, may require food, fluid, med restriction, may need consent, may be invasive or non-invasive.

Nursing responsibilites

Interact with patient in prep for tests and procedures, ensure completion of test in timely manner, interpret test results in relation to patient’s health care needs, note changes in labs and diagnostic findings and communciate w/ the provider, interact w/ patient after test/procedure and provide support, therapeutic interventions and education.

Complete blood count lab [CBC]

White blood cells 3.3 – 10.7 bil/L

Red Blood Cells (RBC) 3.87 – 5.08 tril/L (female); 4.31 – 5.48 tril/L (male)

Hemoglobin (Hgb) 12.1 – 15 g/dL (female); 13.5 – 17g/dL (male)

Hematocrit (Hct) 35.4 – 44.2 % (female); 40.1 – 50.1% (male)

Platelets (Plt) 150 – 400 bil/L

Used to diagnose, evaluate, and monitor bacterial and viral infections, anemias, and leukemic disorders. Show anagram

Leukopenia (autoimmune, bone marrow problem, cancer, increased risk of infection)

Low neutrophils – critical – reverse isolation

Leukocytosis (infection, inflammatory response, certain medications, stress)

Thrombocytopenia – low platelets (inability to clot, what symptoms? Bruising, bleeding) (Bleeding precautions! Hold ASA, subq heparin, electric razor, watch for bleeding gums, blood in stool or urine)

Thrombocytosis – high platelets (increased risk blood clots)

Anemia - transfuse <7 (Why? Acute blood loss, GI bleed) (symptoms pallor, fatigue, weakness, SOB, pica, maybe even decreased spO2 due to inability to carry adequate O2 to body systems) encourage foods high in protein and iron

Ploycythemia Vera – bone marrow makes too many RBC, itchy skin, increased risk of blood clots (hydrate!)

Hemoglobin – females mature between 12-15, males between 13-17

Hematocrit multiply hemoglobin range by 3

WBC associated conditons

WBC up= leukocytosis, WBC down= leukopenia

Steriods [potentially], medication, or infection can cause WBC to go up. Cancr in bone marrow can decrease WBC

Anemia

Shortness of breath, low iron, weakness, easily bruised, cold, bleed trauma, diet, choldbirth, rbc too high= polysideria

Hemoglobin down, hemocrit down, rbc down

platelets

too high thrombopenia, too low thrombocytosis. potential risk of blood clots, avoid cutting oneself. Most common for blood transfusion for RBC <7

Basic Metabolic panel

• Sodium 135-145

• potassium 3.5-5.2

• chloride 98-110

• carbon Dioxide 22-32

• Glucose 60-99 fasting, 60-139 random [steroids can affect glucose]

• Calcium 8.4-10.4

• BUN 8-22

• creatinine 0.60-1.40

• GFR >60

If BUN and creatine abnormal kidney function could be off. GFR higher the better

Sodium

hyponatrimic- low Na, hypernatrimia- high Na

how to treat hyponatrimic- restrict fluids or add sodium

how to treat hypernatrimia- add water

potassium

if 3.3 or 3.4 probably give potassium supplemnet. Heart problems can arise if too high.

Comprehensive metabolic Panel

Includes all labs in BMP plus liver enzymes, bilirubin, protein, and albumin

Protein (6.2 – 8.1)

Albumin (3.5 – 4.9)

Alkaline Phosphatase (ALP) (33 -120)

Aspartate Aminotransferase (AST) (0 – 34)

Alanine Aminotransferase (ALT) (9-47)

Bilirubin (0.3 – 1.2)

Other electrolytes

magnesium 1.7- 2.5

Phosphorus 2.3 - 4.3

Tends to be ordered in ICU, or magnesium on cardiac floors (afib low mag)

Urinalysis

things to look for: color, clarity, glucose, ketones {diabetic poorly controlled, dehydrated, keto diet low carb}, specific gravity [ higher=more concentrated, lower = less concentrated], blood visible to eye, RBC seen under microscope, pH, protein, NITRATES, LEUKOCYTES, WBC, BACTERIA [ these four = UTI ]

Cultures

Urine, wound, blood, stool, sputum, throat.

Culture insensitivity tells what antibiotic is affective against that specific culture. requires a clean sample to be taken like a clean catch from a urine sample which consist of cleaning th earea around and uriniating a little before urinating in the cup.

Many bacteria are resistant to common abx. A sensitivity analysis is a useful tool to help quickly determine if bacteria are resistant to certain drugs

Most cultures are taken prior to pt being placed on ABX. If pt is already on ABX, make lab/provider aware of what kind

Be sure to label all specimens appropriately – typically computerized in hospital

Urine culture

Clean catch

Clean area surrounding urethra

Start midstream

Fill sterile specimen cup

The initial release of urine flushes the urethra.

Send specimen to lab immediately

Wound culture

Use a culture kit

Remove superficial debris

Gently swab

Avoid touching swab to intact skin

Place swab in culture tube.

Need a specimen from deep in the wound

Classic pseudomonas

Blood culture

COLLECT BEFORE STARTING ANTIBIOTICS

DRAW 2 CULTURES FROM 2 SEPARATE SITES

Stool Studies

Lab will not test for C. diff is stool is formed

Can also test for occult blood

Sputum Culture

Sputum= thick and sticky

Try not to contaminate with saliva or sinus drainage

Encourage deep breathing

Provide with sterile specimen cup

Collect as soon as possible

Throat Culture

Swab the inflamed or ulcerated area of the throat

Say ahhhh

Place swab or applicator in culturette tube with it’s medium

coagulation labs

Pt, APTT, and INR are all used to determine how thin blood is

according to INR an average person blood should be 1 or < 1 thick.

If on meds to thin blood for conditions like bloot clots, heart valve, afib, INR should be checked for about 2 - 3.5, if blood lvl is 1 its too thick.

If on heparin apt 60-100

PT think pre teen

INR count 123

Drug lvls

vancomycin is ordered by pharm to give inital dose after checking condition, wuse patients lvls to base next dose off inital dose. Peak trough

Some with narrow therapeutic ranges

Lipids

• Chloesterol <200

• triglyeride <150

• HDL [good chloesterol] >40

• LDL [Bad chloesterol} <130 high risk >100

• non HDL {bad} <160

• chloesterol/ HDL ration <5

In order for a lipid panel to be accurate a person must have been fasting for 12 hrs. Understand what a lipd panel is and what its testing.

cardiac markers

Creatinine Kinase (CK) (40 – 230)

Troponin (0 – 0.05)

0.06 – 0.19 indeterminate for myocardial damage

>0.19 highly suggestive for myocardial damage.

Elevated in coronary syndrome and MI, may also increase with myocardial damage like myocarditis, pericarditis, contusion, and cardioversion), myocardial strain like CHF, pulmonary HTN, and PE) or sepsis and afib. Sometimes also elevated with renal failure. An elevated troponin is a predictor of poor outcomes regardless of its cause

troponin much more specific to the cardiac muscle. Creatinine kinase is elevated for muscle damage.

ABG’s

Arterial blood gases measure the acidity (pH) and the levels of oxygen and carbon dioxide in the blood from an artery. This test is use to find out how well your lungs are able to move O2 into the blood and remove CO2 from the blood. Sample after drawn needs to be kept cool.

Trends

Labs are a snapshot in time. The most powerful way to look at them is to trend them and look at previous labs.

Lab Errors

Hemolysis – false readings

Mislabeling

Using an incorrect tube

Collecting at wrong time

Stored at wrong temperature. Hemolysis can be caused by incorrect needle size, improper tube mixing or tube filling, having a tourniquet on for a long time, or with difficult draws

K high – is it hemolyzed

Fasting vs non fasting, peak/trough

The lab is one part of the picture - you must assess your patient to see if your assessment supports the lab. Does the lab need to be repeated?

Critical lab values

Extremely low or high lab values that require clinical intervention and immediate action. Require read backMust contact provider and document contact and ordered intervention

phase of testing

pretest , intratest, posttest

Assessment, planning, implementation (diagnostic, therapeutic, and educative), and evaluation is part of each phase of testing

Pretest- Assessment

Assessment

Assess patient’s health history, physical, and psychosocial status in relation to test.

Assess patient’s knowledge concerning reason for testing and of test procedure

Assess patient and family questions and concerns

Any potential cultural or belief system barriers?

Recognize potential interfering factors that may affect test outcomes

Pretest- Planning

Obtain written consent, if required

Schedule or check on timing of test

Complete any required forms

Be sure patient is prepped and available at designated time

Incorporate family in preparation if appropriate

Verify preparation and any precautions to be taken by patient and by staff performing test.

Pretest- implementation

Diagnostic: Be aware of history of patient’s complaints and known or suspected conditions associated with test, Review related test results, Determine patient’s understanding and level of preparedness for testing

Therapeutic: Respond to patient’s concerns/fears. Therapeutic interventions: relaxation techniques, medications

Educative; Let patient know what to expect during and after test

Instruct patient and family regarding pretest prep and restrictions

Pretest- evaluation

Evaluate patient’s understanding of reason for test and of procedure, Evaluate patient’s ability to follow preparation and to tolerate actual procedure

Intratest- Assessment

Obtain baseline vital signs if indicated, did patient follow test prep, if not notify appropriate staff, all required equipemnt accessible and in good woking order, ensure proper procedure is followed, recongnize any interfering factors, ensure safety of patient and staff.

Intratest- panning

Verify patient, procedure, and body part to be tested

Verify consent obtained

Prioritize and clarify timing of test

Encourage communication

Ensure test is performed properly

Provide for proper handling, labeling and transport of any specimens

Intratest- implementation

Diagnostic:Monitor patient,Observe for S/S of discomfort,Assess for S/S of stress, infection, allergic reaction, and trauma

Therapeutic: Address patient’s concerns and anxieties, Therapeutic interventions like relaxation techniques and medications

Educative: Keep patient informed about test process and expected outcome.

Intratest evaluation

Evaluate ongoing response to test/procedure

Evaluate patient’s ability to follow intratest instructions

Posttest- Assessment

Assess physical, emotional, and mental status after test

Monitor for complications

Assess patient’s understanding of posttest requirements or restrictions

Assess patient’s ability to follow posttest therapeutic regimen

Assess patient and family questions and concerns

Assess patient and family’s fears/anxieties regarding potential test results

Posttest- planning

schedule up follow up if necessary, inform patient about expectations regarding how and when they will receive test results, verify any precautions to be taken by patient and family following the procedure

Posttest- implementation

Diagnostic: Determine patient’s tolerance of test, Observe for S/S of complications, Assess for altered physical, emotional, or mental status following test or procedure

Therapeutic: Address concerns and anxieties, Provide therapeutic interventions, Ensure safety

Educative: Reinforce patient and family teaching regarding posttest instructions

Posttest- Evaluation

Evaluate patient’s ability to follow up with provider to discuss test results

Evaluate patient’s ability to follow posttest instructions

Evaluate results in relation to patient’s symptoms and other test results

X-rays

Typically no food, fluid, activity, or medication restrictions

Bone X-rays

Evaluate bone pain and trauma

Identify fractures, deformities, dislocations, degeneration

Chest X-rays (CXR)

Identify foreign bodies, position of lines, tubes, and devices, pneumonia, fractures, TB

Ultrasound

Sometimes there are fluid restrictions or requirements depending on the area being scanned

.Used to visualize and assess organs, provide guidance in biopsies, and assist in diagnosing certain cancers, fluid collections, masses, infections, and obstructions

Can also ultrasound heart to assess valves and structural abnormalities, veins to assess for DVT, and carotid arteries to assess for blockages. Abdominal ultrasound usually require fluid restrictions and possibly fasting for 8 hours

Bladder ultrasound usually requires 3-4 cups of water within 90 minutes of test

Some ultrasounds have no restrictions or requirements

CT- computer tomography

Used to visualize and assess internal organs/structures for abnormal or absent anatomic features, abscess, aneurysm, cancer, masses, infection, or presence of disease

May be ordered with or without IV contrast

Assess for allergy to contrast – prep if necessary

Assess kidney function prior to contrast

If patient takes Metformin, may need to hold prior to test with contrast and for 48 hours following test

MRI/MRA

no metal in room so having a pacemaker is a contraindication

Magnetic Resonance Imaging (MRI)

Looks at vessels

Magnetic Resonance Angiography (MRA)

Looks at blood flow and vessels. cons claustriphobia, costly

PET Scan
Positron Emission Tomography

Assess blood flow and metabolic processes, assist with cancer diagnosis and tumor staging,

No alcohol, tobacco, or caffeine for 24 hours prior

No excessive exercise for 72 hours prior

No metal in exam field

Calm state

Drugs that alter glucose can alter results

Monitor for delayed allergic reaction

Increase fluids for 24-48 hours

Flush toilet immediately after voiding and wash hands

Dye eliminated in 6 – 24 hours

Caregivers must wear gloves for 24 hours post procedure when discarding urine.

Abdomen, brain, breast, heart, pelvis Anxiety can impact brain function

Endoscopy

Colonoscopy

EGD

Bronchoscopy

Cystoscopy

Require consent and prob anesthesia