Intro. to Common Blood Tests

Question 1

Breakdown of blood components

Answer 1

Question 2

plasma vs. cellular components

Question 3

erythrocytes (RBCs)

Answer 3

• red blood cells
• make of 45% of total blood
• too high = erythrocytosis
• too low = anemia

Question 4

leukocytes (WBCs)

Answer 4

• white blood cells
• less than 1% of totall blood
• Neutrophils
• lymphocytes
• monocytes
• eosinophils
• basophils
• “NEVER LET MONKEYS EAT BANANAS”

Question 5

platelets

Answer 5

• THROMBOCYTES
• less than 1% of blood

Question 6

plasma

Answer 6

• fluid portion of blood (composed primarily of water) is called plasma

Question 7

Serum

Answer 7

• refers to the substrate remaining when the fibrinogen has been removed from the plasma
• all that remains after blood has been allowed to clot

Question 8

Venous blood

Answer 8

• easier to obtain
• refrences ranges obtain to venous blood unless otherwise stated

Question 9

arterial blood

Answer 9

• oxygenated blood coming from the heart
• used to measure blood gases
• usually obtained from radial artery

Question 10

Complete Blood Count (CBC) with differential

Answer 10

• Performed on whole blood collected in lavender-topped tube (contains the anticoagulant EDTA)
• Main data obtained:
  
  • RBC count (total # of RBC in a microliter of blood)
  • Mean corpuscular volume (MCV)
  • RBC distribution width (RDW)
  • Hemoglobin (Hgb)
  • Hematocrit (Hct)
  • Platelet count
  • WBC count
    
    • WBC differential

Question 11

Recording CBC

Answer 11

• EX:
  
  • 55% Segs
  • 35% Lymphs
  • 6% Monocytes
  • 3% Eosinophils
  • 1% Basophils
  • No Bands

Question 12

hemoglobin

Answer 12

• Hgb
• concentration of hemoglobin, the main component of RBCs, in g/dL

Question 13

hematocrit

Answer 13

• Hct
• measure of the percentage of total blood volume that is made up by the RBCs
  • proportional volume of total blood occupied by erythrocytes

Question 14

(total) white blood cell count

Answer 14

• total number of WBCs in a microliter of blood

Question 15

WBC differential

Answer 15

• The differential usually gives the percentage of each type of leukocyte within the total (per microliter)
• too high = leukocytosis
• too low = leukopenia
• may also give / calculate the absolute count of each type of leukocyte
  
  • Neutrophils / Immature neutrophils (“Bands”)
  • Eosinophils
  • Basophils
  • Lymphocytes
  • Monocytes
• image = normal values

Question 16

platelet count

Answer 16

• total number of platelets in a microliter of blood
• Too high = thrombocytosis
• Too low = thrombocytopenia

Question 17

RBC indices (MCV & RDW)

Answer 17

• “RBC indices” = describe appearance of RBCs
• Mean corpuscular volume (MCV) – expresses the average volume, or size, of an RBC
  
  • “Normocytic” – 80-100 fL (just right)
  • “Microcytic” - <80 (too small!)
  • “Macrocytic” - >100 (too big!)
• RBC Distribution Width (RDW) – indication of the variation in RBC size (“anisocytosis”)

Question 18

Basic Metabolic Profile (BMP)

Answer 18

• sodium
  
  • 136-146 mEq/L
  • major extracellular space cation
• potassium
  
  • 3.5-5.1 mEq/L
  • major intracellular space cation
• chloride
  
  • 98-107 mEq/L
  • major anion in extracellular space
• bicarbonate
  
  • 22-29 mEq/L
  • about 95% of total C02 content in plasma is in form of bicarbonate anion (HCO3)
• blood urea nitrogen
  
  • BUN
  • 6-20 mg/dL
  • Measures the nitrogen component of urea – the end product of protein metabolism, kidneys excrete in urine
• creatinine
  
  • 0.6-1.3 mg/dL
  • Metabolic product of skeletal muscle contraction, kidneys excrete in urine
• glucose
  
  • fasting at least 8 hrs
  • 74 -100 mg/dL
• calcium
  
  • 8.6-10.2 mg/dL
  • Muscle contraction, electrical transmission (nerve / cardiac), blood clotting

** many labs also calculate estimated GFR (eGFR)

** in image, Ca2+ should be above and after glucose

Question 19

Complete Metabolic Profile (CMP)

Answer 19

• includes all BMP …. PLUS
• ALBUMIN 3.4 -4.8 g/dL
• TOTAL PROTEIN 6.4 – 8.3 g/dL
• ALKALINE PHOSPHATASE (ALP) 53-128 U*/L **
• ALANINE AMINOTRANSFERASE (ALT) <45 U/L
• ASPARTATE AMINOTRANSERASE (AST) <31 U/L
• TOTAL BILIRUBIN 0-2.0 mg/dL