Lecture 1/22

• the density of deionized water is 1 g/mL
• balances and centrifuges must be callibrated once a year
• balances usually have units in grams or milligrams
• the most common type of balance used in the lab is the analytical balance, which usually goes out to milligrams
• balances are used to calibrate pipettes
• balances should be kept in low traffic areas since they are sensitive and should not be moved
• centrifuges are used to separate particles from liquids in a suspension
• a centrifuge must be balanced before starting
• the matrix of a specimen refers to the qualities of specimen, including viscosity, color, clarity, and source
• the viscosity is the thickness of the specimen
• plasma is thicker or more viscous than water
• specimen considerations include the matrix, condition of specimen, collection, and storage
• the serum/plasma should be a pale yellow in color

  the clarity of the specimen should be clear

  the viscosity of the specimen should be similar to maple syrup
• collection considerations include using the proper tube, prepping the patient properly (eg. lipid, glucose must be fbs), temperature requirements (eg. ammonia must be put on ice and spun ASAP); photosensitivy requirements
• storage considerations - most common: refrigerate after spinning down and removing serum

  protect from light using special aliquot

  some specimens frozen with special aliquot

  least common - keep specimen at RT

  add to specimen (e.g. HCl to urine for calcium testing)
• the QC must have the same matrix as the patient specimen, but clarity doesnt have to be the same
• plasma after spinning down looks peach to red cherry; some analytes cannot be run as RBC contents have been released; specimen is said to be _______

  hemolysis; hemolyzed
• if patient had fatty meal, serum/plasma may look hazy/cloudy; some analytes cannot be run

  lipemic
• some patients with liver disorders have issues breaking down RBC; may have bilirubin in blood; looks greenish/brown; called ______; specimen is said to be ______

  icterus; icteric
• if the patient is very and on anticoagulant, the blood takes longer to clot in tube; if spun too early what occurs?

  serum coagulates, or fibrin strands present
• phlebotomy is the act of obtaining a blood specimen by puncturing vein with needle
• the preferred site for phlebotomy is the antecubital fossa
• the ante cubital fossa is anterior of the elbow
• the tourniquet should be applied 4 inches above the site in order to stop venous blood, causing the vein to distend
• direct pressure should be applied to the site until it stops bleeding
• a gauze with tape should be applied for 20 minutes
• We cannot draw blood from an IV site
• Only nurses can draw blood through an IV site
• veins move because as one ages, the collagen degrades
• We cannot draw blood from the side of a mastectomy
• What to do if patient has IV

  1. draw from other arm
  2. use the back of the hand
  3. tourniquet and draw site must be distal to the IV or below
  4. cannot draw proximal or above IV
• If only the arm with an IV is available, you must as nurse to shut off IV, wait 20 minutes, and waste first tube of blood
• The order of draw is blood cultures, light blue, red, marble, green or marble green, lavender, grey, pink/brown/dark blue
• sodium citrate for coagulation studies

  light blue
• if light blue is first tube to be drawn, youmust waste a red tube first
• no additive

  red
• SST

  marble or mustard yellow plastic
• sodium/lithium heparin

  green
• liquid used to dilute specimen; what's added to specimen

  diluent
• liquid used to reduce concentration of analyte we are looking to quantify

  diluent