Podcast
Questions and Answers
Which of the following is NOT one of the seven base units recognized worldwide?
Which of the following is NOT one of the seven base units recognized worldwide?
- Length (meter, m)
- Mass (kilogram, kg)
- Time (second, s)
- Energy (joule, J) (correct)
Plasma is the acellular portion of whole blood.
Plasma is the acellular portion of whole blood.
True (A)
What are the primary constituents of whole blood?
What are the primary constituents of whole blood?
Red blood cells, white blood cells, platelets, and plasma.
Serum is the liquid that remains after the __________ clot is removed from plasma.
Serum is the liquid that remains after the __________ clot is removed from plasma.
Match the following substances with their definitions:
Match the following substances with their definitions:
What does specificity refer to in medical testing?
What does specificity refer to in medical testing?
True or False: A lower specificity indicates a higher chance of false positives.
True or False: A lower specificity indicates a higher chance of false positives.
What are the two measures commonly calculated for diagnostic tests?
What are the two measures commonly calculated for diagnostic tests?
In the context of a screening test, FN stands for ___________.
In the context of a screening test, FN stands for ___________.
Match the following terms with their definitions:
Match the following terms with their definitions:
Which formula is used to calculate sensitivity?
Which formula is used to calculate sensitivity?
True or False: A true positive (TP) indicates a diseased person who is detected by the test.
True or False: A true positive (TP) indicates a diseased person who is detected by the test.
The total number of participants in a test is represented by ___________.
The total number of participants in a test is represented by ___________.
What is indicated by a test with 100% sensitivity?
What is indicated by a test with 100% sensitivity?
A highly sensitive test guarantees high specificity.
A highly sensitive test guarantees high specificity.
What is one condition associated with high phenylalanine concentrations that can lead to intellectual disability?
What is one condition associated with high phenylalanine concentrations that can lead to intellectual disability?
A test is considered highly sensitive when the chance of a __________ result is low.
A test is considered highly sensitive when the chance of a __________ result is low.
Match the following sensitivity and specificity outcomes in diagnostic testing:
Match the following sensitivity and specificity outcomes in diagnostic testing:
When are highly sensitive tests preferred?
When are highly sensitive tests preferred?
It is acceptable to use less sensitive tests if the consequence of a false negative is significant.
It is acceptable to use less sensitive tests if the consequence of a false negative is significant.
Reference ranges can be inaccurate if physiologic variables such as age and __________ are not controlled for.
Reference ranges can be inaccurate if physiologic variables such as age and __________ are not controlled for.
What happens to LDL-cholesterol levels as age increases?
What happens to LDL-cholesterol levels as age increases?
The fasting blood glucose reference range for adults is 70–110 mg/dL.
The fasting blood glucose reference range for adults is 70–110 mg/dL.
Name one inherited ethnic laboratory test that is more common in individuals of sub-Saharan African ancestry.
Name one inherited ethnic laboratory test that is more common in individuals of sub-Saharan African ancestry.
The serum creatinine reference range for children aged 1-5 years is approximately _____ mg/dL.
The serum creatinine reference range for children aged 1-5 years is approximately _____ mg/dL.
Match the following genetic conditions with their associated ancestry:
Match the following genetic conditions with their associated ancestry:
Which of the following is the fasting blood glucose reference range for children aged 2 years and older?
Which of the following is the fasting blood glucose reference range for children aged 2 years and older?
Age significantly influences all laboratory values.
Age significantly influences all laboratory values.
What is the impact of ancestry on laboratory test values?
What is the impact of ancestry on laboratory test values?
What is home testing primarily used for?
What is home testing primarily used for?
Baseline studies are only useful when reference values are identical among all patients.
Baseline studies are only useful when reference values are identical among all patients.
What are two popular types of home testing kits mentioned?
What are two popular types of home testing kits mentioned?
The FDA maintains a searchable list of approved home-testing kits under the Office of In Vitro __________ and Radiological Health.
The FDA maintains a searchable list of approved home-testing kits under the Office of In Vitro __________ and Radiological Health.
What condition can lovastatin cause in a small percentage of patients?
What condition can lovastatin cause in a small percentage of patients?
Match the testing kit to the condition it screens for:
Match the testing kit to the condition it screens for:
Baseline laboratory values are also used to establish relative __________ goals.
Baseline laboratory values are also used to establish relative __________ goals.
Non-FDA-approved home testing kits are not available for purchase.
Non-FDA-approved home testing kits are not available for purchase.
What is the reference range for serum potassium concentration?
What is the reference range for serum potassium concentration?
A potassium concentration of 5.5 mEq/L does not require further testing if there are no ECG changes.
A potassium concentration of 5.5 mEq/L does not require further testing if there are no ECG changes.
Name one possible cause of falsely elevated potassium levels.
Name one possible cause of falsely elevated potassium levels.
The sensitivity, specificity, and __________ value are important in selecting an assay and interpreting its results.
The sensitivity, specificity, and __________ value are important in selecting an assay and interpreting its results.
Match the following causes of falsely elevated potassium with their descriptions:
Match the following causes of falsely elevated potassium with their descriptions:
What is a common risk factor for hyperkalemia?
What is a common risk factor for hyperkalemia?
Real-time, in vivo mobile testing will likely remain uncommon in the future.
Real-time, in vivo mobile testing will likely remain uncommon in the future.
What does POC stand for in the context of testing?
What does POC stand for in the context of testing?
Flashcards
Test Sensitivity
Test Sensitivity
The ability of a test to correctly identify individuals who have a specific disease. A test with 100% sensitivity will always be positive in patients with the disease.
False Negative
False Negative
A false negative result occurs when a test incorrectly indicates that a person does not have a disease when they actually do.
Test Specificity
Test Specificity
A test is highly specific if it only produces positive results in individuals who actually have the disease, minimizing false positives.
False Positive
False Positive
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Reference Range
Reference Range
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Physiologic Variables
Physiologic Variables
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Asymptomatic Disease
Asymptomatic Disease
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Phenylketonuria (PKU)
Phenylketonuria (PKU)
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Specimen
Specimen
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Plasma
Plasma
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Serum
Serum
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Whole Blood
Whole Blood
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Rationale for Ordering Laboratory Tests
Rationale for Ordering Laboratory Tests
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Sensitivity
Sensitivity
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Specificity
Specificity
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False Negative (FN)
False Negative (FN)
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False Positive (FP)
False Positive (FP)
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True Positive Rate
True Positive Rate
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True Negative Rate
True Negative Rate
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Accuracy
Accuracy
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Reliability
Reliability
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Age-related lab changes
Age-related lab changes
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Children's reference ranges
Children's reference ranges
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Ethnic and genetic influences on labs
Ethnic and genetic influences on labs
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Sickle cell anemia
Sickle cell anemia
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Thalassemia
Thalassemia
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Glucose-6-phosphate dehydrogenase (G6PD) deficiency
Glucose-6-phosphate dehydrogenase (G6PD) deficiency
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A-G6PD variant
A-G6PD variant
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Home Testing
Home Testing
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Patient-Directed Testing
Patient-Directed Testing
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Baseline Tests
Baseline Tests
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Baseline Studies
Baseline Studies
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Study Notes
Laboratory Testing
- Used to detect disease, guide treatment, monitor response to treatment, and monitor disease progression
- Imperfect science; may yield false negatives or false positives
Definitions
- Accuracy: The extent to which the mean measurement is close to the true value
- Precision: Assay reproducibility (agreement of results when the specimen is assayed many times)
- Analyte: The substance measured by the assay; some substances (e.g., phenytoin, calcium) are bound to proteins. The unbound fraction is physiologically active, but total is typically measured in routine assays.
- Reference Range: A statistically derived numerical range from a sample of healthy individuals; values outside it are not necessarily abnormal but increase the probability of clinical significance.
Quantitative Tests
- Report results as exact numeric measurements (e.g., serum potassium, creatinine clearances)
- Values are assessed in the context of a specific reference range.
Qualitative Tests
- Report results as either positive or negative.
- Exact quantities may be measured, but the final result is reported in categories (e.g., negative, trace, 1+, 2+, etc.)
- The result of tests (e.g., pregnancy tests, bacterial wound cultures) is used to decide on further testing.
Non-invasive vs Invasive
- Noninvasive: Examines fluids or other substances without penetrating the skin or body (e.g., urine, exhaled air)
- Invasive: Examines fluids or tissues with a needle, tube, device, or scope (e.g., venous blood, skin biopsy). These are generally less convenient than noninvasive tests.
Biomarker
- A characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to exposure/intervention.
- Examples: tumor markers, HbA1c to assess average blood sugar levels.
Predictive Value
- Used to assess test reliability.
- Predictive value of a positive test: Percentage of positives that are true positives. Increases with higher prevalence and sensitivity/specificity of the test.
- Predictive value of a negative test: Percentage of negatives that are true negatives. Increases with higher prevalence and specificity/sensitivity of the test.
Objectives
- Reader should be able to differentiate between accuracy and precision, quantitative and qualitative tests, reference ranges, factors affecting them, sensitivity and specificity, and potential sources of laboratory errors.
- Explain the pros and cons of different testing methods (point-of-care vs at-home).
- Describe how to logically interpret lab results.
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Description
Test your knowledge on medical testing concepts and the components of whole blood. This quiz covers base units, blood constituents, specificity in testing, and important diagnostic measures. Ideal for students and professionals in healthcare and biology.
