M7: SPECIMEN PROCESS

• Test results are compromised due to improper collection, incorrect procedure, incorrect storage, incorrect processing, and incorrect transportation
• To avoid compromised test results, we must follow the proper procedures during the PRE-ANALYTICAL PHASE
• Studies show that approximately 46% to 68% of laboratory errors occur PRIOR TO ANALYSIS (Pre-Analytical Phase)
• It is the responsibility of the medical technologist to follow all the appropriate steps required when performing PRE-ANALYTICAL PHASE
• Venipuncture


  • Medical technologist/ Phlebotomist must have the proper knowledge and skills in performing
• Mixing Tubes by Inversion


  1. Gentle inversion of the specimen tube to evenly distribute or mix the additive

  2. Number of inversion depends on additive present in the tube
• Transporting Specimen


  1. Avoid rough handling to prevent hemolysis, activation of platelets, and activation of coagulation

  2. Specimen tubes should be transported with the stopper to avoid contact between contents and stopper, minimize agitation, and aid clot formation for serum tubes

  3. Specimen tubes should be placed in a liquid tight closure plastic bag with a biohazard symbol and a slip pocket for paperwork
• Body Temperature


  • Specimen should be transported at a near body temperature of approximately 37 degrees Celsius
  • Tubes should be pre-warmed at 37 degrees Celsius and portable heat blocks are used during transport
  • Portable heat blocks can hold temperature for at least 15 minutes from removal from the incubator
  • Heel warmer can be used for specimens that can withstand a temperature slightly higher than 37 degrees Celsius
• Chilled Specimen


  • Chilling slows the metabolic process
  • Specimen tube should be completely submerged in crushed ice and water slurry during transport and immediately tested or refrigerated
• Light-Sensitive Specimen


  • The phlebotomist should wrap the tube with aluminum foil or use light-blocking, amber-colored container
• Blood Specimen Processing


  1. Identified (must contain name, age, birthday, and initials of phlebotomist)

  2. Logged or accessioned (most hospitals now use HIS)

  3. Sorted by department and type of processing (Hematology, Microbiology, etc.)

  4. Evaluated for specimen suitability
• Reasons for Specimen Rejection


  • Improper Specimen Identification
  • Contaminated Specimen
  • Inadequate volume (Specimen is insufficient or "Quality not Sufficient" (QNS))
  • Hemolysis
  • Incorrect Collection Time
  • Wrong Tube for Collection
  • Specimen is exposed to light
  • Outdated/ Expired tube
  • Procedure did not follow testing time limits
  • Improper handling (Improper mixing)
  • Delay or error in processing
• Delivery Time Limits


  1. Routine blood specimen is expected to reach/delivered in the laboratory within 45 minutes

  2. Centrifugation needed by the specimen should be done in 1 hour

  3. Hematology specimens with EDTA SHOULD NOT be centrifuged
• Time Limit Exceptions


  A specimen that is marked as "STAT" or "EMERGENGY" takes PRIORITY over all other specimen in terms of transportation, processing, and testing
• Tests with Exceptions to the Time Limit Rule


  • Blood smear from EDTA (Prepared 1 hour from collection)
  • EDTA specimen for CBC (Analyzed within 6 hours but is stable 24 hours from collection at room temperature)
  • EDTA specimen for ESR (Tested 4 hours (room temperature) and 12 hours (Refrigerated))
  • EDTA specimen for Retuculocyte counts (Stable for 6 hours (room temperature) and 72 hours if refrigerated)
  • Glucose test drawn in sodium fluoride tubes (Stable for 24 hours at room temperature but stable for up to 48 hours when refrigerated at 2-8 degrees Celsius)
  • Prothrombin time (Stable for 24 hours) and partial thromboplastin time (PTT) (Should be analyzed within 4 hours from collection)

  
• Centrifugation


  1. Tubes of the same size and volume should be balanced inside the centrifuge

  2. Leave the cover of the tubes to avoid contamination, evaporation, forming of aerosols, and changes in the pH of the specimen

  3. Plasma specimen collected in tubes with anticoagulants should be centrifuged immediately and without delay

  4. Serum specimen needs to be completely clotted prior to centrifugation (normally takes 30 to 60 minutes at room temperature)
• Aliquot


  Portion of a sample specimen taken for chemical analysis or testing
• Aliquot Preparation


  1. Aliquot is done by transferring a portion of the specimen into 1 or more tubes

  2. The labels should be the same to the specimen

  3. Specimens with different anticoagulants should not be put in the same aliquot tubes

  4. Upon transferring into another tube, cover it immediately
• OSHA ACT (RA 11058) Required Protective Equipment


  • Gloves, laboratory gowns/coats, and masks
• When processing specimen inside the laboratory, medtechs are exposed to blood and other infectious organisms, for this reason OSHA requires wearing PPES
• Timed Samples


  • Collection of specimen follows a certain time or schedule
  • Samples collected too early or late can cause false decrease or increase in the results
• Timed Sample Examples


  • Glucose tolerance test
  • 2-hour post-prandial blood sugar
  • Lactose tolerance test
• To Prepare Aliquot


  1. Transfer a portion of the specimen into 1 or more tubes

  2. Labels should be the same as the specimen

  3. Specimens with different anticoagulants should not be put in the same aliquot tubes

  4. Upon transferring into another tube, cover it immediately
• OSHA ACT (RA 11058) REQUIRED PROTECTIVE EQUIPMENT WORN WHEN PROCESSING SPECIMEN
• Protective equipment


  Gloves, laboratory gowns/coats, and masks
• Timed Samples


  1. Collection of specimen follows a certain time or schedule

  2. Samples collected too early or late can cause false decrease or increase in the results
• Timed Samples


  • Glucose tolerance test
  • 2-hour post-prandial blood sugar
  • Lactose tolerance test
• Glucose Tolerance Test


  1. Draw a fasting blood glucose sample then Analyze

  2. Ask the patient to drink the flavored glucose solution

  3. Timing for the next collection begins when the patient finishes the glucose solution

  4. 1 hr. sample: Draw blood, Analyze

  5. 2 hr. sample: Draw blood, Analyze

  6. 3 hr. sample: Draw blood, Analyze

  
• Lactose Tolerance Test


  1. The patient is asked to drink a standardized amount of lactose solution based on body weight in place of the glucose

  2. A blood collection is similar to a 2-hour GTT

  3. Glucose levels will raise no more than 20 mg/dL from the fasting sample result if the patient is LACTOSE INTOLERANT

  
• 1. Hour Post-Prandial Blood Sugar


  1. Fast at least 12 hours

  2. Draw a fasting blood sugar sample- Analyze

  3. Patient is instructed a full meal after blood is drawn for the FBS sample

  4. 2-hour sample- draw blood-analyze
• After eating a full meal, food is digested, which will increase sugar. In response to this, the pancreas will release INSULIN to move sugar from the blood into the cells. So, within 2 hours of eating insulin and blood-glucose level SHOULD RETURN TO NORMAL. If the glucose is still high, the patient most likely has diabetes.
• Chain of Custody


  Documentation of who had possession of the evidence, from the time of collection to the time of analysis and beyond
• Goal: to maintain the integrity of the evidence
• Chain of Custody documentation


  • Date, time and place the specimen is obtained
  • Signature of the person from whom the specimen was taken
  • Identification or signature of the person who handles the specimen
• Tests that require Chain of Custody


  • Drug Testing
  • Blood Alcohol Samples
  • Paternity Testing
• Drug Testing


  • For medical, legal and employment purposes
  • Sample for processing urine- ease of collection and longer half-life of substances
• Blood Alcohol Samples


  • Usually ordered for purposes related to treatment but could also be used for industrial or job-related purposes (insurance claims, employment)
  • Cleansing of site: soap and water OR non-alcoholic antiseptic solution (benzalkonium chloride- Zephiran Chloride)
  • Collection: to prevent the escape of volatile alcohol, tubes must be completely filled and not uncapped for longer than necessary (usually gray-top sodium fluoride glass tubes)
• Paternity Testing


  • Performed to determine the probability that a specific individual fathered a particular child
  • Mother, child and alleged father are tested
  • Samples: Blood, Buccal swabs
• Point of Care Testing (POCT)


  Analytical Testing activities provided within the institution but performed outside the physical facilities of the clinical laboratory
• Advantages of POCT


  • Reduced turn-around time
  • Rapid data availability
  • Self-contained and user-friendly instruments