Questions and Answers
Which factor is known to increase the concentration of analytes in a specimen after food ingestion?
What is a potential effect of vigorous hand exercise, such as fist clenching, on potassium levels?
Which hormone is known to show a postprandial rise in concentration after eating?
What type of variations are usually transient and easily controlled in laboratory tests?
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Which accrediting agency requires laboratories to document specimen collection methods?
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What is the primary reason for applying a tourniquet before specimen collection?
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Which of the following substances is likely to show an increase in concentration due to strenuous exercise?
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What effect does tobacco smoking have on laboratory test results?
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What can cause specimen quality to be compromised due to incomplete barrier formation in gel tubes?
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Which of the following is a common error in specimen collection that could lead to contamination?
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What is the most problematic additive carry-over in specimen collection?
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How can evaporation of specimens affect electrolytes?
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Which error is associated with prolonged tourniquet application?
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What is the potential effect of severe hemolysis on analytes present in serum or plasma?
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Which analytes become clinically significant after 24 hours of unseparated serum or plasma?
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How does bilirubin interfere with serum measurements?
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What is a consequence of lipemia in a serum sample?
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Which analytic constituent is least stable if not removed from the clot within 30 minutes?
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What corrective measure can help prevent the shift of electrolytes leading to erroneous potassium levels?
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After how many hours does serum become unstable if not separated from the clot?
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Which of the following analytes might be significantly affected by hemoconcentration?
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What might happen to triglycerides when serum exceeds a specific concentration?
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Which electrolyte is prone to false increases due to shifts from high metabolic activity of white blood cells (WBCs)?
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What is the optimal storage temperature for serum or plasma if analysis is to be delayed for longer than 4 hours?
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Which of the following is a reason for specimen rejection?
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Which additive is specifically used to prevent blood from clotting in vacuum tubes?
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What can excessive centrifugation lead to in specimen handling?
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Which analytes must be chilled during transport and storage at 4℃?
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What is a common effect of hemolysis on laboratory results?
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Which of the following is an additive in evacuated tubes that helps in clotting?
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What does an antiglycolytic agent do in specimen handling?
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Which condition could result from the movement of water into cells during specimen collection?
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What is the effect of low temperature storage on LDH isoenzymes?
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What is a common cause of hematoma formation during venipuncture?
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Which action can lead to a hemolyzed specimen?
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Why is skin puncture often preferred in geriatric patients?
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Which factor is NOT associated with the risk of hemolysis?
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What is the primary indication of a hematoma?
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Which of the following is a potential complication from inappropriate blood collection in premature infants?
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How should the bevel of the needle be positioned for optimal venipuncture?
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Why is capillary blood collection preferred for infants and young children?
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What is syncope more commonly referred to as?
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Which condition must be reserved exclusively for parenteral therapy in sick infants?
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Which technique can contribute to the failure of blood to enter the syringe or ETS?
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Which of the following is a late general complication of improper blood collection techniques?
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What can cause excessive probing during venipuncture?
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Study Notes
Laboratory Responsibilities
- Laboratories must establish standard procedures for patient preparation, sample collection, transportation, and preservation to minimize errors.
- Accreditation agencies like CAP require detailed manuals documenting specimen collection methods and error minimization.
Pre-Collection Causes of Variation
- Factors influencing analyte concentration include tourniquet application, exercise, and tobacco smoking.
- Diet-related changes in lab tests often result from postprandial responses, causing transient increases in various analytes.
Hemolysis and Hematoma Prevention
- Hemolysis can occur from using excessively small needles, rapid plunger pulls, or vigorous mixing.
- Hematomas may develop due to needle size mismatch, excessive probing, or improper pressure application post-venipuncture.
Capillary Blood Collection
- Capillary punctures are preferred for infants and young children due to smaller blood volume and risks associated with venipuncture.
- Microcapillary blood collections are essential when venipuncture is not feasible.
Electrolyte and Analyte Stability
- Certain substances like potassium, phosphorus, and glucose are unstable and can significantly alter lab results if not processed quickly.
- Blood samples must be separated from clotting agents within 30 minutes to maintain analyte stability.
Specimen Storage and Transport
- Serum or plasma should be stored at 4-6℃ if analysis is delayed beyond four hours to prevent degradation.
- Specific specimens require chilling (e.g., ammonia, blood gases, lactic acid) during transport.
Additives in Evacuated Tubes
- Additives in evacuated tubes prevent clotting and glycolysis, ensuring the integrity of the sample.
- Common anticoagulants include EDTA, citrate, and heparin, with each having specific functions in the collection process.
Common Errors in Specimen Collection
- Misidentification, mislabeling, short draws, inadequate mixing, and the use of wrong anticoagulants are frequent errors.
- Proper order of draw is critical to avoid contamination and ensure accurate results.
General Guidelines
- Excessive centrifugation can cause cell lysis, elevating potassium and LDH levels.
- Electrolyte levels can be affected by evaporation prior to testing, compromising specimen quality.
- Clear labeling, appropriate handling, and timely delivery to the lab are essential for accurate diagnostic testing.
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Description
This quiz covers key concepts and procedures related to laboratory tests, particularly focusing on creatinine, serum proteins, and the impact of short-term exercise on potassium levels and muscle enzymes. Understand the importance of standardized procedures in minimizing errors during patient preparation.
