Lab Values Podcast by NURSING.com (Nursing Podcast, normal lab values for nurses for NCLEX®) by NURSING.com (NRSNG)

Determine the significance and clinical use of iron levels in clinical practice

Iron – Fe

Measures the amount of Fe in the bloodstream.

Evaluates:

• Sufficient Fe level
  • oxygen transport
  • proper hemoglobin & RBC production

Iron (Fe) is an element that is an important component of hemoglobin in red blood cells.

Iron aids hemoglobin's transport of oxygen from the lungs to all the cells of the body.

The storage form of iron is ferritin. Iron is transported in the blood by a protein called transferrin.

Identify:

• Blood loss
• Hemochromatosis
• Malabsorption of iron
• Iron overload

Type of anemia:

• Thalassemia
• Sideroblastic anemia
• Iron deficient anemia

Normal –

50-175 μg/dL

Collection:

• plasma separator tube

What would cause Increased Levels of Iron?

• Hemochromatosis
• Lead toxicity
• Iron poisoning
• Acute liver disease
• Multiple blood transfusions
• Hemolytic anemia
• Sideroblastic anemia

What would cause Decreased Levels of Iron?

• Blood Loss:
  • Gastrointestinal (GI) bleeding
  • Heavy menstruation
  • Chronic hematuria
• Hypothyroidism
• Iron-deficiency anemia
• Inadequate absorption of iron

1. Hemoglobin
   1. Normal Value Range
   2. Pathophysiology
   3. Special considerations
   4. Elevated hemoglobin
   5. Decreased hemoglobin

1. Normal value range
   1. Males – 13.5-16.5 g/dL
   2. Females – 12.0 – 15.0 g/dL
2. Pathophysiology
   1. Protein attached to red blood cell
   2. Iron based protein
   3. 4 groups
      1. 2 alpha
      2. 2 beta
   4. Has a high affinity (attraction) for oxygen
      1. Oxyhemoglobin
         1. Has oxygen attached
      2. Deoxyhemoglobin
         1. Oxygen has been released
   5. Oxyhemoglobin Dissociation Curve
      1. Oxygen saturation
      2. Shift to the right
         1. Partial pressure is higher
         2. HGB attraction to oxygen is lower
         3. Oxygen becomes less "sticky" and wants to be released
         4. Causes
            1. ↓pH
            2. ↑pCO2
            3. ↑Temperature
      3. Shift to the left
         1. Partial pressure is lower
         2. HGB attraction is higher
         3. Oxygen wants to stay "stuck" to HGB
         4. Causes
            1. ↑pH
            2. ↓pCO2
            3. ↓Temperature
3. Special considerations
   1. Submit in lavender top tube
   2. Be cautious with phlebotomy technique
      1. Reduce hemolysis with proper tubing and syringes
4. Elevated HGB values
   1. Polycythemia vera
      1. Treatments
         1. Blood letting
         2. Increased water intake
         3. Some medications
   2. Dehydration
   3. Lung disease
      1. Pulmonary fibrosis
      2. COPD
   4. Certain medical therapies
      1. EPO supplementation
5. Decreased HGB values
   1. Thalassemia
   2. Blood loss
   3. Sickle Cell anemia
   4. Aplastic anemia
   5. Cancers

1. Assess for signs of anemia
   1. Tachycardia
   2. Fatigue
   3. Shortness of breath
   4. Decreased SaO2
   5. Pallor

1. Blood transfusions as necessary
2. Treat primary cause of anemia

1. Lab Values
2. Oxygenation

1. Hematocrit
   1. Normal Value Range
   2. Pathophysiology
   3. Special considerations
   4. Elevations in lab results
   5. Decreased HCT levels

1. Normal value range
   1. HCT measured in percentage
   2. Males – 41-50%
   3. Females – 36-44%
2. Pathophysiology
   1. Measurement of total pRBCs compared to rest of blood volume
   2. Helps to indicate anemia
   3. Often measured with HGB (hemoglobin)
3. Special considerations
   1. Lavender top tube (EDTA)
   2. Be cautious with technique
      1. Do not force sample into tube
      2. Can cause hemolysis
      3. Alters results
4. Causes of HCT elevation
   1. Dehydration
      1. Change in % compared to total blood volume
   2. Respiratory disease
      1. COPD
      2. Pulmonary fibrosis
         1. Increased need for oxygen -> increased need for RBC production
   3. Polycythemia vera
      1. RBC overproduction due to bone marrow cancer
      2. Treatment includes bloodletting and increasing water consumption (also some medications)
5. Causes of decreased HCT
   1. Blood loss
      1. Trauma
      2. Hemorrhage
      3. Treatment
         1. Stop bleeding
         2. Transfuse blood
   2. Anemia
      1. Kidney disease
         1. Decrease in EPO production
         2. Treatment
            1. Supplement with EPO
      2. Pregnancy
         1. Relative to increase total blood volume
   3. Leukemia
      1. Decreased bone marrow production causes ↓ RBC
      2. Treat leukemia via oncology pathways
         1. Chemotherapy
         2. Radiation
         3. Bone marrow transplant

1. Assess for signs of anemia
   1. Tachycardia
   2. Fatigue
   3. Shortness of breath
   4. Decreased SaO2
   5. Pallor

1. Blood transfusions as necessary
2. Treat primary cause of anemia
3. Use oncologic methods to treat leukemia
4. Bloodletting (phlebotomy) for polycythemia patients

1. Lab Values
2. Oxygenation

Determine the significance and clinical use of Erythrocyte Sedimentation Rate in clinical practice

Erythrocyte Sedimentation Rate- ESR

The Erythrocyte Sedimentation Rate (ESR) test measures sedimentation of Red Blood Cells (RBCs).

In normal conditions, RBCs settle or sediment very little.

Inflammation affects proteins in the blood causing RBCs to stick and settle together out of the liquid portion of the blood.

Identifies inflammation which assists in diagnosing:

• Cancer
• Infection
• Autoimmune diseases

Normal – 0-20 mm/hr

Increased

Conditions:

• Anemia
• Chronic Renal Failure
• Systemic Lupus Erythematosus (SLE)
• Infection
• Tuberculosis
• Pregnancy
• Polymyalgia Rheumatica
• Multiple myeloma

Medications:

• Oral contraceptives
• Theophylline
• Vitamin A

What would cause decreased levels?

Decreased

Conditions:

• Sickle cell anemia
• Polycythemia Vera
• Leukocytosis
• Congestive Heart Failure (CHF)

Medications:

• Aspirin
• Cortisone
• Quinine

Determine the significance and clinical use of D-Dimer in clinical practice

D-Dimer- DDI

Measurement of D-Dimer evaluates the amount of byproduct produced as part of fibrinolysis

D-dimer (DDI) is a product of fibrinolysis

D-dimer levels are elevated in the setting of clot breakdown, and will be significantly elevated in the setting of Disseminated Intravascular Coagulation (DIC).

Identify and monitor

Disseminated Intravascular Coagulation (DIC)

Rule out a blood clot:

• Pulmonary Embolism (PE)
• Deep Vein Thrombosis (DVT)
• Stroke

Normal – ≤ 250 ng/mL

Collection:

• Light blue lab tube

Increased

• Surgery
• Trauma
• Infection
• Cancer
• Heart attack
• Pregnancy
• Deep Vein Thrombosis (DVT)
• Disseminated Intravascular Coagulation (DIC)

Indicates a lack of the substance that is released during the breakdown of a blood clot (i.e. lack of blood clots, or lack of fibrinolysis)

Determine the significance and clinical use of C-Reactive Protein in clinical practice

C-Reactive Protein – CRP

C-reactive protein (CRP) is made in the liver in response to inflammation

Measures CRP in the blood

• Increases quickly
• Decreases quickly

Monitor or Identify:

• Inflammation in the body
  • Appendicitis
  • Pelvic Inflammatory Disease (PID)
  • Crohn's
  • Ulcerative Colitis
  • Rheumatoid Arthritis (RA)
  • Lupus (SLE – Systemic Lupus Erythematosus)

Evaluate:

• Coronary Artery Disease (CAD)
  • Cholesterol level – atherosclerosis

Normal –

Collection:

• Serum separator tube

Increased=Inflammation

• Bacterial Infection
• Crohn's Disease
• Inflammatory Bowel Disease
• Lupus
• Rheumatoid Arthritis (RA)
• Pregnancy – estrogen
• Myocardial Infarction (MI)

Decreased=resolving inflammation

Medications that reduce inflammation:

• NSAIDs
• Statins
• Steroids

1. Creatinine
   1. Normal Value Range
   2. Pathophysiology
   3. Special considerations
   4. Elevations in creatinine
   5. Decreases in creatinine

1. Normal values
   1. 0.7 – 1.4 mg/dL
2. Pathophysiology
   1. Muscle breakdown and use
      1. Creatine -> creatinine
   2. Released into bloodstream
      1. Filtered through kidneys
      2. Excreted in urine
   3. Creatinine more specific to kidney function
3. Special considerations
   1. Green top
   2. Submitted with renal panels or chems
   3. Creatinine clearance
      1. Tests creatinine in urine
      2. Compare to serum creatinine
      3. 24 hour urine
         1. Toss first urine sample, then start
         2. On ice
4. Increased creatinine values
   1. Renal disease
   2. Rhabdomyolysis
      1. Muscle breakdown
      2. Trauma
      3. Extreme workouts
   3. Congestive heart failure
   4. Dehydration
   5. Shock
5. Decreased creatinine values
   1. Loss of muscle mass
   2. Muscular dystrophy
   3. Decreased protein intake
   4. Pregnancy
   5. Liver disease

1. Assess patient's nutritional status
2. Assess urine output
3. Consider other causes for increase in creatinine
   1. Muscle

1. Treat cause of renal insufficiency
   1. Dialysis vs medication

1. Lab Values
2. Elimination

Determine the significance and clinical use of measuring Creatinine Clearance in clinical practice

Creatinine Clearance – CrCl

Healthy kidneys remove creatinine from the blood. It then passes out of your body through urine. Creatinine is created in the body as a byproduct from normal wear and tear on muscles and protein in your diet.

Creatinine Clearance is a test that compares the level of creatinine in the blood against the level in the urine and evaluates Glomerular Filtration Rate. Hydration, blood volume status, blood pressure, and the state of the glomeruli impact GFR.

Remember that GFR is the amount of blood cleaned each minute by tiny filters in your kidneys called glomeruli.

An increase in CrCl indicates an increase in GFR.

The creatinine clearance test is done when your healthcare provider thinks that the eGFR result given with your blood creatinine level may not be accurate. This would be in patients who have diabetes, those with HF, those with kidney disease, and is sometimes evaluated in those with hypertension.

• Kidney Function
  • GFR
• Diabetes
• Heart Failure
• Hypertension

Normal – Creatinine clearance rates go down as you age

• Male: 97 to 137 mL/min
• Female: 88 to 128 mL/min

For every decade after age 40, a normal test result is 6.5 mL/min less than the numbers above.

Collection:

• Plasma separator tube for serum
• Urine is collected for 24 H in a plastic container
• First void is flushed
• Date and time recorded, and urine collected and stored at room temperature
• Processed once collection is complete

Increased Creatinine Clearance→ Increased GFR

• Pregnancy- higher blood volume
• Large protein intake
• Exercise

The kidneys are solely responsible for removing Creatinine from the blood. If kidney function is declining, the creatinine level increases in the blood, but less creatinine is excreted into the urine.

Decreased Creatinine Clearance→ Decreased GFR

• Abnormal kidney function
• Poor perfusion
• Dehydration
• Bladder obstruction
• Nephrotoxic medications

1. Cholesterol
   1. Normal Value Range
   2. Pathophysiology
   3. Any special considerations when drawing the lab (i.e. on ice, etc.)
   4. Too High: Causes, Symptoms, Treatments
   5. Too Low: Causes, Symptoms, Treatments

1. Normal values
2. Pathophysiology
   1. Functions
      1. Essential in cell membrane formation
      2. Precursor to Vitamin D
      3. Precursor to hormone formation
      4. Synthesized in liver
   2. Lipoproteins
      1. High Density Lipoprotein (HDL)
         1. Removes excess levels of cholesterol
         2. Goal >60 mg/dL
      2. Low Density Lipoprotein (LDL)
         1. Contributes to plaque buildup
         2. Goal
   3. Excess cholesterol and lipid buildup
      1. Contributes to:
         1. Atherosclerosis
         2. Arteriosclerosis
3. Special considerations
   1. Submit in green top tube
   2. Ensure patient fasts
      1. Food intake can alter results
4. Elevated cholesterol levels
   1. Obesity
   2. Cushing's Disease
   3. Hypothyroidism
   4. Ischemic heart disease
   5. Diabetes
   6. Liver disease
      1. Non-alcoholic Fatty Liver Disease
   7. Malabsorption
      1. For all patients, attempt to decrease cholesterol levels with diet/exercise;
      2. If no improvement, incorporate statins (unless immediate concern for impending disease (such as stroke or MI)
5. Decreased cholesterol levels
   1. Burns
   2. Hyperthyroidism
   3. Chronic Myelocytic Leukemia
   4. Malnutrition
   5. Anorexia

1. Assess fitness/activity lifestyle and goals
2. Assess nutritional status, goals and lifestyle

1. Incorporate low fat diet
2. Incorporate fitness/activity increase as tolerated

1. Lab Values
2. Nutrition

1. Educate patient on utilizing a low fat/low cholesterol diet
2. Educate patient on appropriate fitness or activity level increase dependent on tolerance

1. BNP
   1. Normal Value Range
   2. Pathophysiology
   3. Special considerations
   4. Lab value elevations

1. Normal value range
   1. 100 pg/mL
2. Pathophysiology
   1. Increased pressure overload due to increased SVR or volume
   2. Ventricular stretching causes release of BNP into bloodstream
   3. BNP released to aid in stress due to overload by:
      1. Increases excretion of sodium in urine = natriuresis
         1. Sodium follows water
      2. Decreased intravascular volume
      3. Decreased workload on the heart = improved cardiac function
3. Special considerations
   1. Lavender tube (EDTA)
   2. NT-proBNP may be requested instead
      1. Submit in serum separator tube (tiger top)
4. Elevated lab values
   1. >100 pg/mL – heart failure likely
   2. The higher the value, the more likely the diagnosis of heart failure

1. Assess patient for acute exacerbation of heart failure
   1. Lung sounds
   2. Oxygen status
      1. Need for supplemental oxygen
2. Radiographic evaluation
3. May need diagnostics for evaluation
   1. Echocardiogram can determine contractility function

1. Treatment
   1. Treat heart failure
      1. Diurese
      2. Improve contractility

1. Lab Values
2. Perfusion