Published: 20 Aug 2024

Errors in Test Results

While false negative and positive results are rare, your healthcare provider may order multiple tests to ensure an accurate diagnosis.

Factors Affecting Test Accuracy

Several factors can influence the accuracy of test results, including:

- Foods and beverages
- Medications
- Stress levels
- Intense exercise
- Lab procedure inconsistencies
- Underlying health conditions

False Negative and Positive Results

- False positive: Test indicates a disease or condition that is not present.
- False negative: Test indicates the absence of a disease or condition that is actually present.

These errors are infrequent but more likely with specific test types or improper testing procedures.

Units of Measurement

- Reference ranges for blood tests are denoted in:
- dL (deciliters) in the United States
- L (liters) in Sweden

- Mass concentration:
- g/dL (grams per deciliter) in the United States

- International units (IU) are based on biological activity.

- Enzymatic activity:
- kat (katal) for enzymes like AST, ALT, LD, and v-GT

- Molar concentration:
- mol/L (moles per liter) preferred in many global regions, including the United Kingdom, Europe, Australia, and New Zealand