MLS LE 4

• Laboratory Samples


  • Routine Samples
  • ASAP Samples
  • STAT Samples (Short Turnaround Time)
• Routine Samples


  For diagnosis and monitoring, collected early morning or during collection sweeps or schedule, collected from the outpatient department (OPD) patients
• ASAP Samples


  Response time varies from each laboratory
• STAT Samples


  For managing of critical cases, collected, analyzed, and results are reported immediately
• Factors that can influence the composition of blood

  • Age
  • Altitude
  • Body position
  • Dehydration
  • Diet
  • Diurnal variation
  • Drugs
  • Environment
  • Exercise
  • Gender
  • Pregnancy
  • Smoking
  • Stress
• To try to eliminate these factors, we try to collect blood when the body is in a basal state
• Basal State


  Body's state after 8 to 12 hours of fasting and abstention from strenuous exercise
• Fasting and timed collection includes

  • Analytes with Diurnal Variation
  • Therapeutic Drug Monitoring
  • Glucose Tolerance Tests
  • Lactose Tolerance Tests

  
• Fasting Collection


  Involves analytes affected by diet, drinking water is encouraged to avoid dehydration, NPO "Nothing by Mouth" (no food and water)
• If the signage of bed is fasting, not NPO, confirm with the nurse if the patient can drink water while fasting
• Fasting Collection

  • The patient refrains from eating for a period of time (8-12 hrs), refrains from exercise, phlebotomist will take note of the time of last meal and time of collection
• Laboratory Tests for Fasting Collection

  • Fasting Blood Sugar
  • Lipid Panel

  
• Timed Collection


  Taken to determine the changes in the level of some substances that are to be monitored over time, samples should be collected at the precise time
• Laboratory Tests for Timed Collection

  • Myoglobin
  • Troponin I
  • CPK-MB
  • Prothrombin Time
  • aPTT
• Reasons for Timed Samples

  • Measurement of the body's ability to metabolize a particular substance
  • Monitoring changes in a patient's condition (such as a steady decrease in hemoglobin)
  • Determining blood levels of medications
  • Measuring substances that exhibit diurnal variation (normal changes in blood levels at different times of the day)
  • Measurement of cardiac markers following acute myocardial infarction
  • Monitoring anticoagulant therapy

  
• Diurnal Variation


  Substances that exhibit diurnal variation change their levels at different times of the day, recommended collection time is when they are at their peak level
• Laboratory Tests with Diurnal Variation

  • Plasma Cortisol (peak 8:00 - 10:00 AM)
  • Serum Iron (peak 8:00 - 10:00 AM)
  • Hormones (morning collection)
  • Leukocytes (morning collection)
• Therapeutic Drug Monitoring


  To manage patients being treated with certain drugs in order to help establish a drug dosage, while adjusting the dosage when in combination with other drugs taken, identifying non-compliant patients, maintaining the dosage at a therapeutic (beneficial) level, to avoid drug toxicity
• Time of collection for Therapeutic Drug Monitoring

  Intravenous (IV): 30 minutes (after the medication was given), Intramuscular (IM): 1 hour, Oral Dosage: 1 to 2 hours
• Peak Level


  Shortly after the medication was given
• Trough Level


  Time right before the next dosage is given
• Glucose Tolerance Tests are used for the diagnosis of diabetes mellitus and differentiating it from gestational diabetes (diabetes acquired by pregnant women)

  
• Timed examinations for glucose tolerance test

  • 2-hour Postprandial
  • Classic Glucose Tolerance Test
  • Oral Glucose Tolerance Test
  • Oral Glucose Challenge Test

  
• 2 Hour Postprandial (2HPP)


  For diabetes mellitus, used to monitor insulin therapy, compares the fasting glucose level with the level 2 hours after consuming glucose

  
• 2 Hour Postprandial (2HPP)


  • Patient will first undergo fasting, get the blood sample after fasting for 8-10 hours, test for Fasting Blood Glucose, patient eats full meal (75-100 grams of glucose in the meal or drink), patient fast again for 2 hours (NPO), test again for 2nd Glucose (Postprandial glucose level after 2 hours)

  
• Results Interpretation for 2 Hour Postprandial

  • Normal: Less than 140 mg/dL for the 2nd glucose
  • High: 140-180 mg/dL

  
• Classic Glucose Tolerance Test

  Done for diabetes mellitus and gestational diabetes, the patient drinks a standard glucose load/preparation (75/100 g) and returns for testing on an hourly basis up to 6 hours in length

  
• 1. Hour 100-Gram Oral Glucose Tolerance Test for Screening in Pregnancy

  • Carpenter/Coustan: Fasting ≥ 95 mg/dL, 1 Hour ≥ 180 mg/dL, 2 Hours ≥ 155 mg/dL, 3 Hours ≥ 140 mg/dL
  • National Diabetes Data Group: Fasting ≥ 105 mg/dL, 1 Hour ≥ 190 mg/dL, 2 Hours ≥ 165 mg/dL, 3 Hours ≥ 145 mg/dL

  
• Classic Glucose Tolerance Test

  • Patient must eat a balanced diet with 150g carbohydrates for 3 days prior to exposing your patient to fasting for 8-10 hours, test for Fasting Blood Glucose, patient drinks glucose solution (75/100g), inform patient to fast again and of the scheduled collection times, extract blood for glucose testing on scheduled times, some procedures may also be parallel tested with urine glucose

  
• Classic Glucose Tolerance Test Timing

  • Fasting Specimen 6:00 AM
  • Time Finished Intaking 6:05 AM
  • 30 mins. After 6:35 AM
  • 1 hr. After 7:05 AM
  • 2 hrs. After 8:05 AM

  
• 1. Hour Oral Glucose Tolerance Test


  The recommended methods for the diagnosis of diabetes mellitus, same procedure as 2HPP but uses a glucose solutions instead of a full meal as glucose load

  
• 1. Hour Oral Glucose Tolerance Test


  • Patient will 1st undergo fasting, test for Fasting Blood Glucose, patient drinks 75 gm glucose solution, patient fast again for 2 hours, test again for glucose

  
• Results Interpretation for 2-Hour Oral Glucose Tolerance Test

  • Normal: Less than 140 mg/dL for the 2nd glucose
  • Indicative of Diabetes Mellitus: ≥ 200 mg/dL

  
• Oral Glucose Challenge Test


  1. hour glucose screening test or gestational glucose screening test, not quantitative, just screening test, patient drinks 50 gm of glucose solution, abnormal results: > 140 mg/dL

  
• Methods for Gestational Diabetes

  • One-Step Method: Utilizes the same procedure as the diagnostic Oral Glucose Tolerance Test (OGTT) used to diagnose diabetes mellitus
  • Two-Step Method: Done for 2 days, 1st day: Oral Glucose Challenge Test (OGCT) is done, 2nd day: Oral Glucose Tolerance Test (OGTT) is done

  
• Lactose Tolerance Test


  Used to determine if a patient lacks the mucosal lactase that is necessary to convert lactose, or milk sugar, into glucose and galactose, same procedure as a 2-hr OGTT, but the patient drinks a lactose solution instead
• Results Interpretation for Lactose Tolerance Test

  • Lactose Intolerant: Glucose levels will raise no more than 20 mg/dL from the fasting results

  
• Blood cultures are requested in patients with fever and chills, other signs of septicemia, or fever of unknown origin (FUO)
• Blood cultures are collected in sets of 2 (30 or 60 mins apart) right before the spike of fever
• Septicemia


  Happens when microorganisms get access into the blood system