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Flashcards in Diagnostic Reference Ranges & Lab Values Deck (48):
1

Sodium (Na+)

135 - 145 mEq/L

  • Major electrolyte (cation)
  • Regulates extracellular fluid volume -- maintains osmotic pressure and acid-base balance
  • Assists in the transmission of nerve impulses

 

2

Potassium (K+)

3.5 – 5.0 mEq/L

  • Major electrolyte (cation)
  • Regulates
    • Cellular water balance
    • Electrical conduction in muscle cells
    • Acid-base balance
  • Kidneys preserve or excrete potassium based on cellular need
  • Potassium levels are used to evaluate cardiac funciton, renal function, GI function, and need for IV replacement therapy

 

3

Calcium (Ca2+)

9.0 - 10.5 mg/dL (ATI)

8.6 - 10 mg/dL (Saunders)

  • Major electrolyte (cation)
  • Functions in:
    • Bone formation
    • Nerve impulse transmission
    • Contraction of myocardial and skeletal muscle
  • Aid blood clotting by converting prothrombin to thrombin
  • Levels can be affected by
    • Decreased protein levels
    • Anticonvulsant medications

4

Magnesium (Mg2+)

1.3 – 2.1 mEq/L (ATI)

1.6 - 2.6 mg/dL (Saunders)

  • Major electrolyte (cation)
  • Used as an index to determine metabolic activity and renal function
  • Functions
    • Needed for blood clotting mechanism
    • Regulates neuromuscular activity
    • Acts as a cofactor that modifies the activity of many enzymes
    • Has an effect on the metabolism of calcium
  • Acts as a CNS depressant and can reduce respirations and deep tendon reflexes

5

Chloride (Cl-)

97-107 mEq/L (ATI)
98 - 107 mEq/L (Saunders)

• Major electrolyte (anion)

• Major component of interstitial and lymph fluid

6

Hyponatremia

Serum Sodium <135 mEq/L

  • S/S: tachycardia, hypotension, muscle cramps and weakness, lethargy, headache, personality changes, dry mucus membranes
    • Decreased urine specific gravity
  • Causes: GI losses, diuretics, excessive water intake, burns, kidney disease
  • Treatment: based on the cause (treat the cause, not just the symptom)

7

Hypernatremia

Serum Sodium >145 mEq/L

  • S/S: irritability, extreme thirst, fever, dry and flushed skin, dry tongue and mucus membranes, muscle twitching, diminished or absent DTRs (late sign), altered cerebral function
    • Increased urine specific gravity
  • Causes: Increased water loss, increased ingestion of sodium; corticosteroids; Cushing's syndrome; kidney disease; hyperaldosteronism
  • Treatment: based on cause (treat the cause, not just the symptom)

8

Hypokalemia

Serum Potassim <3.5 mEq/L

** Potentially life-threatening b/c every body system is affected. **

S/S

  • Cardiac arrhythmias
  • Weakness and fatigue; hypoactive reflexes
  • Decreased muscle tone, paresthesias (tingling)
  • Shallow respirations
  • Anxiety, lethargy, confusion, coma
  • ST depression; shallow, flat, or inverted T wave; prominent U wave

Causes

  • Diuretics, corticosteroids
  • Increased secretion of aldosterone (Cushing's)
  • GI losses (vomiting, diarrhea, GI bleeding)
  • Extreme sweating
  • Naso-gastric suctioning
  • Inadequat intake
  • Alkalosis, hyperinsulinism

Treatment

  • Potassium replacement
  • NEVER give via IV push, IM, or SubQ
  • No more than 1 mEq/10mL
  • 5 - 10 mEq/hr, never to exceed 20mEq/hr
  • Can cause phlebitis

Foods

  • avocado, bananas, cantaloupe, carrots, fihs, mushrooms, oranges, potatoes, raisins, spinach, strawberries, tomatoes, beef, pork, veal

9

Hyperkalemia

Serum Potassim > 5.0 mEq/L

S/S

  • Slow, weak, irregular heart rate
  • Cardiac arrhythmias
  • Hypotension
  • Weakness of skeletal muscle which can progress  to the point of respiratory failure
  • Muscle twitches progressing to ascending flaccid paralysis
  • Increased GI motility, hyperactive bowel sounds, diarrhea
  • Tall, peaked T waves; flat P waves; widened QRS complexes; prolonged PR intervals

Causes

  • Renal failure, diabetic ketoacidosis, tissue damage

Treatment

  • Kayexelate (fluid, oral; binds with potassium and is excreted – can result in diarrhea)
  • Instruct clients to avoid salt substitutes which often contain potassium
  • Insulin drives potassium into cells and can be used as an intervention

10

Hypocalcemia

Serum Calcium
< 9.0 mg/dL
(ATI)
< 8.6 mg/dL (Saunders)

S/S

  • Decreased heart rate, hypotension, diminished peripheral pulses
  • Irritable skeletal muscles - twitches, cramps, tetany, seizures
  • Paresthesias in lips, nose, ears, and limbs
  • Positive Trousseau's and Chvostek's signs
  • Hyperactive DTR
  • Anxiety, irritability
  • Prolonged ST interval; prolonged QT interval

Causes

  • Vitamin D deficiency
  • Pancreatitis
  • Crohn's
  • End-stage renal disease
  • Hyperphosphatemia

Treatment

  • Calcium supplementation with Vit D
  • Reduction of phosphorous increases calcium

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11

Hypercalcemia

Serum Calcium
> 10.5 mg/dL
(ATI)
> 10 mg/dL (Saunders)

Manifestations

  • Early - increased HR
  • Late - bradycardia that can lead to cardiac arrest
  • Increased BP; bounding peripheral pulses
  • Skeletal muscle weakness can lead to respiratory difficulty
  • Diminished or absent DTRs
  • Disorientation, lethargy, coma
  • Kidney stones, flank pain
  • Decreased motility; hypoactive bowel sounds
  • Shortened ST segment; widened T waves

Causes

  • Hyperparathyroidism
  • Large doses of Vitamin D
  • Thiazide diuretics
  • Malignancy - bone destruction from metastatic tumors

Treatment

  • identify underlying cause

12

Hypomagnesemia

Serum Magnesium 
< 1.2 mEq/L
(ATI)
< 1.6 mEq/L (Saunders)

Manifestations

  • Tachycardia, hypertension
  • Shallow respirations
  • Twitches; paresthesias
  • Positive Chvostek's and Trousseau's signs
  • Hyperreflexia, muscle tremors
  • Confusion, irritability
  • Tall T waves; depressed ST segments

Causes

  • Malnutrition and alcoholism
  • Diarrhea, NG suctioning; Celiac, Crohn's
  • Hyperglycemia
  • Sepsis

Treatment

  • Magnesium administration
  • Hypomagnesemia is often coupled with hypocalcemia -- treat both
  • Foods: avocado, canned white tuna, cauliflower, green leafy vegetables, milk, oatmeal and wheat bran, peanut butter, almonds, peas, potatoes, raisins, yogurt, pork, beef, chicken, soy beans

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13

Hypermagnesemia

Serum Magnesium
> 2.0 mEq/L
(ATI)
> 2.6 mEq/L (Saunders)

Manifestations

  • Bradycardia, dysrhythmias, hypotension,
  • Flushing and skin warmth
  • Decreased respirations; respiratory insufficiency
  • Diminished or absent DTRs; skeletal muscle weakness
  • Drowsiness and lethargy that can progress to coma
  • Prolonged PR interval; widened QRS

Causes

  • Renal failure
  • Increased magnesium intake/administration

Treatment

  • Symptomatic
  • Antidote: calcium gluconate

 

14

Phosphorous

3.0 - 4.5 mg/dL (ATI)

2.7 - 4.5 mg/dL (Saunders)

  • Important component of
    • Bone formation
    • Energy storage and release
    • Urinary acid-base buffering
    • Carbohydrate metabolism
  • Excreted by kidneys
  • High concentrations are stored in bone and skeletal muscle
  • Foods: pumpkin and squash, fish, nuts, whole-grain breads and cereals, dairy products, pork, beef, chicken

15

Blood Urea Nitrogen: BUN

10 - 20 mg/dL (ATI)

8 - 25 mg/dL (Saunders)

  • Elevated levels indicate a slowing of the glomerular rate
  • An increased level may indicate: hepatic or renal disease, dehydration, decreased kidney perfusion, high protein diet, infection, stress, steroid use, GI bleeding.
  • A decreased level may indicate: malnutrition, fluid volume excess, severe hepatic damage.

16

Creatinine (Serum)

General
0.6 - 1.3 mg/dL

Females: 0.5 - 1.1 mg/dL
Males: 0.6 - 1.2 mg/dL

  • Indicator of renal function
  • An increased level may indicate: kidney impairment -- slowing of the glomerular filtration rate
  • A decreased level may indicate: decreased muscle mass

17

Glucose

70 - 105 mg/dL (ATI?)

Fasting
70-110mg/dL (Saunders)

Capillary (finger stick)
60-110mg/dL (Saunders)

2-hr Postprandial
<140mg/dL (Saunders)

  • Glucose is the main source of cellular energy for the body and is essential for brain and erythrocyte function

18

Glycosylated Hemoglobin: HgbA1c

Good Control
7% or lower

Fair Control
7-8%

Poor Control
> 8%

  • Blood glucose bound to hemoglobin
  • Hemoglobin A1C (HgbA1c) is a reflection of well blood glucose levels have been controlled for the past 3 to 4 months

19

WBC

5,000 - 10,000 cells/mm3 (ATI)

4,500 - 11,000 cells/mm3 (Saunders)

  • Function in the immune defense system
  • "Shift to the left" -- an increased number of immature neutrophils is present in the blood
    • Low total WBC count with a left shift indicates a recovery from bone marrow depression or an infection so severe that it demanded more than the bone marrow could release
    • Increased neutrophil count with left shift usually indicates bacterial infection
  • c -- cells have more than the usual number
    • Found in liver disease, Down syndrome, and megaloblastic and pernicious anemia

20

RBC

Women
4.2 - 5.4 million/mm3 (ATI)
4 - 5.5 million/µL (Saunders)

Men
4.7 - 6.1 million/mm3 (ATI)
4.5 - 6.2 million/µL (Saunders)

  • Formed in bone marrow and have a lifespan of 120days
  • Removed from the blood via liver, spleen, and bone marrow

21

Hemoglobin

Women
12-16 g/100mL (ATI)
12-15 g/dL (Saunders)

Men
14-18 g/100mL (ATI)
14-16.5 g/dL (Saunders)

  • Hemoglobin is the main component of erythrocytes and serves as the vehicle for transporting O2 and CO2
  • Important component in determining anemia

22

Hematocrit

Women
37-47%

Men
42-52%

  • Represents RBC mass
  • Important measurement in the identification of anemia or polycythemia

23

Platelet

150,000 - 400,000 /mm3

  • Produced in bone marrow; function in hemostasis
  • Institute bleeding precautions for values below normal
  • Monitor platelet count closely in chemo pts due to risk of thrombocytopenia

24

pH

7.35 - 7.45

25

pCO2

35 - 45 mmHg

26

pO2

80 - 10 mmHg

27

HCO3 (Bicarbonate) - Venous

21 - 26 mmol/L (ATI?)

22-29 mEq/L (Saunders)

28

PT

Prothrombin Time

Normal
11 - 12.5sec (ATI?)
9.5 - 11.3 females (Saunders)
9.6 - 11.8 males (Saunders)

Therapeutic
+/- 2 sec of control value

  • Test used when initiating and maintaining anticoagulant therapy with warfarin (coumadin). 
  • Measures the amount of time it takes in seconds for clot formation
    • Measures the activity of prothrombin, fibrinogen, and factors V, VII, and X
  • Subtherapeutic values may indicate the warfarin dose is too low (non-therapeutic) or Vit K excess.
  • Prolonged values indicate that the patient is at risk for bleeding
    • Warfarin may be reduced or held
    • Pt may be instructed to eat foods high in vit K. 
  • Orally administered anticoagulant therapy usually maintains a PT at 1.5-2x lab control value
  • If PT value is longer than 30sec, initiate bleeding precautions

29

INR

International Normalized Ratio

Normal
1 or 0.7 - 1.8 (ATI?)

Therapeutic
2 - 3 (standard therapy)
3 - 4.5 (high-dose therapy)

  • Test used when initiating and maintaining anticoagulant therapy with warfarin (coumadin) -- generally more accurate than PT.
  • Measures the activity of prothrombin, fibrinogen, and factors V, VII, and X
  • Individualized for each pt.

30

aPTT

Activated Partial Thromboplastin Time

Normal
30 - 40 sec
(ATI)
20 - 36 sec (Saunders)

Therapeutic
1.5-2x normal/control value

  • Assesses the intrinsic clotting cascade and action of factors II, V, VIII, IX, XI, and XII.
    • PTT is prolonged whenever any of these factors is deficient (ex: hemophilia, DIC).
  • Monitors heparin therapy.
    • Do not draw sample from an arm into which heparin is infusing!
  • If the aPTT value is prolonged (longer than 90sec), initiate bleeding precautions

 

31

Digoxin: Therapeutic Blood Level

0.5 - 2.0 ng/mL

32

Lithium: Therapeutic Blood Level

0.8 - 1.4 mEq/L (ATI?)

0.5 - 1.2 mEq/L (Saunders)

33

Dilantin: Therapeutic Blood Level

10 - 20 mcg/mL

34

Theophylline: Therapeutic Blood Level

10 - 20 mcg/mL

35

Urine Specific Gravity

Normal
1.005 - 1.030
(ATI?)
1.016 - 1.022 (Saunders)

  • An increased level may indicate
    • Decreased kidney perfusion
    • Congestive heart failure
    • Inappropriate antidiuretic hormone secretion
  • A decreased level may indicate
    • Chronic kidney disease
    • Diabetes insipidus
    • Use of diuretics
    • Lithium toxicity
    • Decreased ability to concentrate urine (often seen in the older adult)

36

D-dimer Test

  • Blood test that measures clot formation and lysis that results from the degredation of fibrin
  • Helps to diagnose the presence of thrombus in conditions such as DVT, pulmonary embolism, or stroke
  • Used to diagnose disseminated intravascular coagulation (DIC)

37

Erythrocyte Sedimentation Rate

0 to 30 mm/hr
(depending on age of client)

  • Rate at which erythrocytes settle out of anticoagulated blood in 1 hr
  • Helps to detect illnesses associated with inflammation, acute and chronic infection, advanced neoplasm, and tissue necrosis or infarction

38

Serum Iron

 

Female
50 - 170 mcg/dL

Male
65 - 175 mcg/dL

  • Iron acts as a carrier of oxygen from the lungs to the tissues and indirectly aids in the return of carbon dioxide to the lungs
  • Found predominantly in hemoglobin
  • Level of iron will be increased if the client ingested iron before test

39

Albumin

3.4 - 5 g/dL

  • Main plasma protein of blood
  • Transports bilirubin, fatty acids, medications, hormones, and other substances that are insoluble in water
  • Increased in conditions such as:
    • Dehydration
    • Diarrhea
    • Metastatic carcinoma
  • Decreased in conditions such as:
    • Acute infections
    • Ascites
    • Alcoholism
  • Presence of detectable albumin (protein) in the urine is indicative of abnormal renal function

40

ALT
Alanine Aminotransferase

10 - 40 units/L

  • Used to identify hepatocellular injury and inflammation of the liver
  • Used to monitor improvement or worsening of liver disease

41

AST
Aspartate Aminotransferase

10 - 30 units/L

  • Used to evaluate a client with suspected hepatocellular disease, injury, or inflammation
  • May also be used along with cardiac markers to evaluate coronary artery occlusive disease

42

Amylase

25 - 151 units/L

  • Produced by the pancreas and salivary glands; aids in the digestion of complex carbohydrates and is excreted by the kidneys
  • Acute pancreatitis -- level may exceed 5x the normal value
    • Level starts to rise ~6hrs after onset of pain
    • Peaks at ~24hrs
    • Returns to normal 2-3days after onset
  • Chronic pancreatitis -- level usually doesn't exceed 3x normal value

43

Lipids

Total Cholesterol: 140 - 199 mg/dL

LDL: < 130 mg/dL

HDL: 30 - 70 mg/dL

Triglycerides: <200 mg/dL

  • Blood lipids consist of:
    • Cholesterol
    • Triglycerides
    • Phospholipids
  • Increased colesterol levels, LDL levels, and triglyceride levels pace the client at risk for coronary artery disease
  • HDL helps protect against coronary artery disease
  • Oral contraceptives may increase lipid levels

44

Acetaminophen: Therapeutic Blood Level

 

10 - 20 mcg/L

45

Magnesium Sulfate: Therapeutic Blood Level

 

4 - 7 mg/dL

46

Salicylate: Therapeutic Blood Level

 

100 -250 mcg/mL

47

Valproic Acid (Depakene): Therapeutic Blood Level

 

50 - 100 mcg/mL

48

IOP

Intraocular pressure

An expected reference range for IOP is between 10 and 21 mm/Hg.