LABORATORY

• Types of specimens analyzed in the clinical chemistry laboratory

  • Blood
  • Urine
  • Cerebrospinal fluid (CSF)
  • Ascitic fluid
  • Peritoneal fluid
• Whole blood


  Contains plasma and formed elements
• Plasma


  Liquid portion of the unclotted blood, contains albumin, globulin and fibrinogen
• Serum


  Liquid portion of the clotted blood, contains albumin and globulin
• Types of urine samples

  • 24-hour sample
  • Random sample
  • Timed sample
• Cerebrospinal fluid (CSF)


  Used in tests like meningitis confirmation, to calculate lactate, glucose and protein
• In clinical chemistry laboratory, Protein and Glucose are assessed in CSF
• Serum


  • Certain substances like the lipemia clearing factor (LPL) are co-precipitated during clotting
  • Clearer than plasma
  • There is a potential interference produced by anticoagulants
• Timing of specimen collections

  • Fasting
  • Random
  • 24 Hour
  • Postprandial
• Classification of methods as to sample requirements

  • Macro method (≥1 mL blood)
  • Micro method (0.1-0.9 mL blood)
  • Ultramicro method (0.01-0.09 mL blood)
  • Nanoliter method (0.001-0.009 mL blood)
• Prior to blood collection the patients must be given correct instruction on how to prepare for each laboratory test
• Factors contributing to the variations of results

  • Exercise
  • Fasting
  • Diet
  • Posture/Position
  • Tourniquet application
  • Tobacco smoking
  • Alcohol ingestion
  • Stress
  • Drugs
• Physiologic variation


  Changes that occur within the body such as cyclic changes (diurnal or circadian) or those resulting from exercise, diet, stress, gender, age, drugs, posture or underlying medical conditions
• Immediate local complications of venipuncture

  • Localized hemoconcentration or venous stasis
  • Syncope or Fainting
  • Failure of blood to enter the syringe
• Local delayed complications of venipuncture

  • Thrombosis of veins
  • Thrombophlebitis
  • Hematomas
• General late complications of venipuncture

  • Serum hepatitis
  • AIDS
• Types of anticoagulants


  • Oxalates
  • Citrates
  • EDTA
  • Fluoride
  • Heparin
• Rapid separation of serum from the clotted blood is a necessity to prevent various issues
• PISO method


  Potassium is always inside of RBCs, sodium is always outside of RBCs. Whenever -LYSIS occurs, there is an increase of potassium and decrease in sodium.
• Today's technologies allow testing on an impressively wide variety of samples collected from the human body
• Most often, all that is required is a blood sample. However, samples of urine, saliva, sputum, feces, semen, and other bodily fluids and tissues also can be tested
• Some tests can be performed on more than one type of sample
• Sodium


  Always outside of red blood cells
• Potassium


  Always inside of red blood cells
• Whenever -LYSIS occurs


  There is an increase of potassium and decrease in sodium
• Most often, all that is required is a blood sample
• Samples that can be tested

  • Urine
  • Saliva
  • Sputum
  • Feces
  • Semen
  • Other bodily fluids and tissues
• Samples naturally eliminated from the body

  Urine, feces, sputum, semen
• Collecting naturally eliminated samples

  • Usually painless, but can be awkward and unpleasant as they involve elimination of bodily wastes and involve body parts and functions people prefer to keep private
• Semen collection


  1. Male patients ejaculate into a specimen container

  2. Abstinence: 2-5 days

  3. Deliver specimen after collection

  4. Timed collection: start to delivery to the laboratory

  5. Avoid using condoms, lubricants or other potentially contaminating materials
• Semen analysis


  • To test male infertility in couples who are unable to conceive
  • To confirm the success of a vasectomy by checking for sperms in semen
• Semen analysis procedure


  1. Abstain from sex and masturbation for 2 to 5 days before the test

  2. Avoid consumption of alcohol, caffeine, and drugs for 2 to 5 days before the test

  3. Avoid taking herbal supplements or hormone medications

  4. Do not use any lubricant while taking the sample
• Complete parameters of semen analysis

  • Liquefaction Time
  • Volume
  • Color
  • pH
  • Odor
  • Viscosity
  • Motility
  • Viability
  • Morphology
  • Count
  • Fructose content
• Sputum


  Coughed up from as far down in the lungs as possible, relatively thick and not as watery as saliva
• Tests required for sputum

  • Acid Fast Baccilli Smear (AFB Smear)
  • Culture and Sensitivity
• Indication of AFB test

  • To detect mycobacterial infection
  • To diagnose TB (Mycobacterium tuberculosis)
  • Monitor effectiveness of treatment
• Stool collection


  Patients usually collect this sample themselves during toileting, avoiding contamination from other material in the toilet bowl
• Clinical significance of stool analysis

  • Diagnosis of digestive system infections (bacteria, parasites, virus and fungi)
  • Diagnosis of pancreas disorders (inflammation); malabsorption of nutrients (fat)
  • Primary screening test for some types of digestive system malignancy such as colon cancer (occult blood)
  • Primary screening for peptic ulcer disease, and some types of anemia (occult blood)
• Types of urine specimen

  • Random
  • First Morning
  • Midstream clean catch
  • Catheterized
  • 24-Hour (Timed)
• Saliva collection


  May be collected using a swab or by having the patient expectorate into a container without generating sputum