Unit 6 and 7

• Diurnal variation


  Fluctuations in biological processes and functions over the course of a day
• Exercise


  • Increases creatine kinase (CK), aspartate aminotransferase (AST), and lactate dehydrogenase (LD)
  • Increases potassium (0.3 - 1.2 mmol/L for mild to moderate exercise, 2-3 mmol/L for exhaustive exercise)
  • Increases prolactin (in long-distance athletes)
  • Decreases serum gonadotropins and sex steroid (in long-distance athletes)
• Diet


  Can affect various blood components
• Stress


  • Emotional stress can cause transient elevations in WBCs
  • Mental and physical stresses induce the production of ACTH, cortisol, and catecholamines
• Posture


  • Upright position increases hydrostatic pressure, causing a reduction of plasma volume and increased concentration of proteins
  • Albumin and calcium levels may become elevated as one changes position from supine to upright
  • Change in position from lying to standing can cause up to 15% variation in total and HDL cholesterol results
• Tourniquet application


  • May increase serum enzymes, proteins, and protein-bound substances
  • 1 minute application
  • Prolonged application results in venous stasis (hemoconcentration)

  
• Age


  • Newborns have much Hb F, bilirubin concentration rises after birth and peaks at 5 days, infants have lower glucose than adults, alkaline phosphatase and creatinine increase with skeletal growth and muscle development, elderly secrete less T3, PTH, aldosterone, and cortisol, men experience decrease in testosterone after 50, women have increase in gonadotropins after 50
• Gender


  • Men have higher alkaline phosphatase, aminotransferase, creatine kinase, and aldolase levels after puberty
  • Women have lower magnesium, calcium, albumin, Hb, serum iron, and ferritin levels
• Tobacco smoking


  • Increases carboxyhemoglobin, Hb, RBC count, MCV, WBC count, insulin, epinephrine, and growth hormones
  • Decreases sperm counts, motility, and increases abnormal morphology
• Hemolysis


  • Serum/plasma layer is pink or red
  • Falsely increases potassium, magnesium, iron, LD, phosphorus, ammonium, and total protein
  • Serum has slightly higher potassium than plasma
• Alcohol ingestion


  • Increases uric acid, triglycerides, GGT
  • Causes hypoglycemia
• Dehydration


  • Affects RBCs, enzymes, iron, calcium, sodium, and coagulation factors
• Drug therapy


  • Chemotherapy decreases blood cells, especially WBCs and platelets
  • Many drugs are toxic to liver, increasing ALT, AST, LD, and decreasing clotting factors
• Problem areas to avoid in site selection


  • Burns, scars, and tattoos
  • Damaged veins
  • Edema
  • Hematoma
  • Mastectomy
  • Obesity
• Arterial line (A-line or Art-line)


  • Catheter placed in artery (radial) to provide accurate and continuous blood pressure measurement, collect blood gas and other specimens, and administer drugs
  • Never apply tourniquet or perform venipuncture on arm with A-line

  
• Arteriovenous shunt, fistula, or graft


  • Permanent surgical connection of artery and vein for dialysis
  • Has a distinctive "thrill" sensation when palpated
  • Never apply tourniquet or perform venipuncture on arm with shunt
• Blood sampling device


  • Needleless closed device connected to arterial or central venous catheter to collect specimens, reduce infection, prevent needlesticks, and minimize waste (e.g. VAMP from Edwards Lifesciences)

  
• Heparin or saline lock


  • Catheter or cannula with stopcock or diaphragm cap to provide access for medication or blood draw
  • Not recommended for drawing coagulation specimens

  
• Intravenous sites


  • Blood should not be drawn from arm with active IV

  
• Previously active IV sites


  • Blood specimens should not be collected within 24-48 hours of IV discontinuation

  
• Central vascular access devices (CVADs)


  • Tubing inserted into main vein or artery for fluids, medications, pressure monitoring, and blood draw
  • Only specially trained personnel should access
  • Types: Central venous catheter, implanted port, PICC
• Central venous catheter (CVC)

  • Line inserted into large vein (subclavian) and advanced into superior vena cava
• Implanted port


  • Small chamber attached to indwelling line, surgically implanted under skin, commonly in upper chest or arm
• Peripherally inserted central catheter (PICC)


  • Line inserted into peripheral vein and threaded into central venous system, typically in antecubital vein
• Complications associated with blood collection


  • Allergies to equipment/supplies
  • Excessive bleeding
  • Fainting/syncope
  • Nausea and vomiting
  • Pain
  • Petechiae
  • Seizures/convulsions

  
• Hematoma formation


  • Most common venipuncture complication, apply cold compress to reduce swelling

  
• Iatrogenic anemia


  • Removing blood regularly or in large quantities can lead to anemia, life threatened if >10% blood volume removed at once
• Inadvertent arterial puncture


  • Rapidly forming hematoma, blood tube fills very quickly, terminate venipuncture immediately and apply pressure for at least 5 minutes

  
• Infection


  • Risk minimized by using proper aseptic technique
• Nerve injury


  • Causes: poor site selection, inserting needle too deeply/quickly, patient movement, excessive/lateral redirection, blind probing
• Reflux of additive


  • Prevent by keeping patient's arm in downward position, avoid back-and-forth blood movement in tube

  
• Vein damage


  • Caused by numerous punctures, blind probing, improper technique
• Hemoconcentration (venous stasis)


  • Affects specimen quality

  
• Hemolysis


  • Serum/plasma layer pink (slight), dark pink to light red (moderate), dark red (gross)
  • Falsely increases certain analytes
• Partially filled tubes (short draw)


  • Short-draw serum tubes generally acceptable if not hemolyzed and sufficient specimen, underfilled anticoagulant tubes not acceptable
• Specimen contamination


  • Affects specimen quality
• Wrong or expired collection tube


  • Affects specimen quality
• Troubleshooting failed venipuncture


  • Tube position, needle position, tube vacuum
• Lancet


  Sterile, single-use device used to puncture skin for capillary blood collection
• Short-draw serum tubes


  • Generally acceptable for testing as long as the specimen is not hemolyzed and there is sufficient specimen to perform the test
  • Underfilled anticoagulant tubes and most other additive tubes are NOT acceptable for testing