Clinical Chemistry Exam 1 Lecture 2

Preanalytical
Ordering
Collecting
Transporting
Storing
Processing
% of errors due to preanalytical
45-55%
% of errors due to analytical
% of errors due to postanalytical
15%
Analytical
Instrument set-up
QC
Testing
Maintenance (PM)
Personnel
Postanalytical
Interpreting
Recording
Reporting
Stockyard Storage
11 Patient Related Preanalytical Variables
Diet
Exercise
Stress and Anxiety
Posture
Drugs, diuretics, alcohol, smoking, age, gender, and race
Diet NR are typically what type of ranges?
Fasting
What substances are often associated with diet as a preanayltical variable?
Glucose, insulin
Triglycerides
Gastrin
BUN (urea)
As you exercise what happens to your lactic acid?
Increases
As you exercise what happens to your pH?
Decreases
As you exercise what happens to your muscle enzymes (CK, LD, AST)?
Increases
Hyperventilation may cause ____ ___ and secretion of _________ _______
Respiratory alkalosis
Adrenal hormones
Prolonged crying elevates what type of count?
WBC
From lying down to sitting or standing, the position change can cause water flow from the IV space to go where?
Interstitium
Posture results in decreased _____ _____ and an increase in ______ serum components
blood volume
larger
6 Collection-Related Preanalytical variables
Tourniquet
Circadian Variation
Anticoagulants and Separator Gels
Hemolysis
Intravenous Infusions
What will prolonged application of a Tourniquet cause?
Hemoconcentration
What substances are most affected by extended tourniquet usage?
Albumin
Albumin-bound substances
What are most affected by Circadian Variation?
Hormones
Iron
What does Standard Order of Draw reduce the risk of?
An anticoagulant in one tube contaminating blood collected in the following tube
Effects of EDTA contamination: what will decrease
Calcium (Ca) & Magnesium (Mg)
Effects of EDTA contamination: what will increase
Potassium (K)
What is the correct order of draw to avoid EDTA contamination?
Sterile
Light Blue
Red
SST/PST
Green
Lavender
Gray
What will all of the following potentially cause?
Traumatic venipuncture, alcohol swabs, shaking, bad pneumatic tube system
Hemolysis
True or False:
It does not require visible hemolysis to affect tests
True
It does not require visible hemolysis to affect tests – only what?
prolonged serum/cell contact
What substances are most affected by Hemolysis?
Potassium
Iron
Varying enzymes
If a tube that has hemolysis comes to the lab, what should you do?
Reject the sample
With intravenous infusions where should you collect from?
An alternate site if possible
For Intravenous Infusions if necessary how long should you turn off the IV for?
2 minutes
For Intravenous Infusions when collecting and the IV has been turned off where should you collect from?
Below the IV, preferably in different vein
How many mL should you discard after collecting a sample from a patient who is undergoing Intravenous Infusions?
5
Dextrose IV:
Glucose
Saline IV:
Sodium
Chloride
Proteins
Potassium
TPN (parenteral nutrition):
Elevated Lipids
Glucose
Potassium
How many minutes should you allow for a clot to form at room temperature
20-60
With a clot activator how many minutes should you allow for a clot to form?
5-10
True or False:
Green tops / PSTs do not need to clot at all
True
If serum is separated too quickly, what may still be present?
microclots / fibrinogen
If serum is not removed in a timely fashion, what may begin to metabolize glucose?
WBCs / RBCs
True or False:
Refrigeration or freezing kills LD
True
True or False:
Exposure to light decreases bilirubin
True
Prolonged storage causes _____ leakage from RBCs
Potassium
Given the Storage Situation Name the Most Affected Substance:
Freezing
LD
Given the Storage Situation Name the Most Affected Substance:
Light
Bilirubin
Given the Storage Situation Name the Most Affected Substance:
Evaporation
Ketones
Given the Storage Situation Name the Most Affected Substance:
Cell Metabolism
Glucose
Ammonia
Given the Storage Situation Name the Most Affected Substance:
Older Samples
Potassium
What is the term used to describe an elevation of proteins when a patient changes from a lying to a sitting or standing position?
Hemoconcentration
What is the most common cause of postanalytical errors?
Clerical
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