Lab Diagnostics Test

What is the purpose of laboratory testing?

to establish a diagnosis, to rule out a clinical problem, to monitor therapy, to establish a prognosis, to screen for disease, to determine effective drug dosage, and prevent toxicity

What are the common blood collection methods?

• venous- most common

• arterial

• skin puncture

What are the common urine collection methods?

• clean catch

• mid stream

• catheter collected

CSF

• clear, colorless that flows in the ventricles within the brain or around the spinal cord

• collected via a lumbar puncture or spinal tap

What are some way to prevent inaccurate lab results?

• Dont shake tubes

• dont collect specimen from a site on an arm with an IV running

• history of acillary lymph node surgrey or lymphedema

• tourniquet should not be applied for more than a minute

What does a CBC include?

• RBCs - RBC count, hemoglobin, hematocrit, MCH/MCHC, MCV, RDW

• WBCs- WBC count and differential of WBC

• Platelets- platelet count

MCH/MCHC

• indicates the amount of hemoglobin in a RBC

MCV

average size of RBC

RDW

the distribution of different sizes of RBC

Plateletes

important for primary hemostasis/ clot formation

why would you order a CBC?

infection, anemia, bleeding/ bruising, fatigue/weakness, and fever

primary job of neutrophils

• first cells to come in during an inflammatory response to help sterelize a wound

• Best at bacterial infections

what is the most abundt type of WBC

neutrophils

primary job of lymphocytes

• adaptive immunity

• best at viruses and memory for immune system

Primary job of basophils

• seen in allergic reaction to release histamine

primary job of eosinophils

• parasites, allergies, asthma

primary job of monocytes

• clean up crew

• become macrophages

why do you order a BMP?

• to evlaute electrolytes and kidney function

• to evaluate to dehydration and metabolism

what does a BMP include?

• electrolytes

• Kidney

• metabolism

what are the 3 test to test kidney fucntion

• BUN

• Creatinine

• GFR

what does glucose show

source of energy

what does BUN show

• directly related to protein intake

• helps evaluate renal problems and protein metabolism/ breakdown evaluation

what does creatinine show

• helps evlauate renal function

what does the GFR show

• determine kidney function

• best way to determine if kidneys are working properly

sodium

• extracellular cation important for hemostatis

potassium

• intracellular cation

• determines neuromusclar irritability: abnormal levels interfere with muscle contraction

• false evlauation can occur- hemolysis since K+ is intracellular and is relased

chloride

• extracellular anion

• important in maintaining proper water distribution, osmotic pressure, and normal acid base balance

CO2

• most important buffer system in maintining normal body fluid pH

• Venous representation of HCO3-

calcium

• important for bone, teeth, muscle contraction, cardiac muscles, and helps send and recieve signals from CNS.

• 1% is in blood and tissues

• 99% is stored in bone and teeth

why would you order a CMP?

• gives you everything in a BMP

• additonal liver information

• protein information

What are the test that test the liver

• AST

• ALT

• ALKP

• bilirubin

what test does a CMP include that test our protein status

• albumin

• protien

what can a CMP tell us

• problems with the liver

• problems with the biliary system

• problems with protein status

albumin

• major compenent of plasma protiens

• major binding protein in the body

• inlfuenced by nutritional state, hepatic function, and various diseases

totral protein

• determined by nutritonal state, hepatic function, renal function, and various diseae states

• serum protien consist of primarily albumin and globulin

AST

• intravellular enzyme

• presents in large concentration in liver, skeletal muscle, brain, red cells, kidney, and heart

• released into blood stream when tissue is damaged specially in liver injury

ALT

• intracellular enzyme

• present in large concetrations in the liver

• released with tissue damage specially liver

ALKP

• primarily found in liver, bone, intestines, kidney, and placenta

• used to detect liver disease and bone disorders

Bilirubin

• pigment derived from breakdown of hemoglobin

• biotransformed in the liver and excreted in bile and urine

why would we order an urinalysis

• UTIs

• Kidney disease

• diabetes

• hydration status

what is included in a urinalysis

color, clarity, specific gravity, leukocytes, nitrites, blood, ketones, protein, glucose, and miscroscopt

what does a urinalysis tell us?

• infection

• blood present

• protein

• sugar

• concentration/ hydration.

Coagulation studies

• used to evaluate bleeding disorders

PT/INR

• evaluates extrinsic and common coagulation pathways

• most common test used to monitor warfarin therapy

PTT

• evaluates intrinsic and common pathways and adequacy of all coagulation factors

• commonly used to monitor heparin therapy

D- dimer

• one ofthe most terminal fibrin degradation products

• indicates a fibrin clot was gomed and degraded by plasmin

why would we order a D-dimer

• used to help rule out low risk patients for pulmonary emboli

• very sensitive, low specificity