What is the interpretation of abnormal laboratory values?

From the Guidelines

Abnormal laboratory values must be interpreted in the clinical context of a given patient, considering their medical history, medications, and symptoms, rather than relying solely on the laboratory results themselves. When evaluating abnormal liver tests, for example, a detailed history, inventory of medications, and physical examination are crucial, including an assessment of the patient’s risk factors for liver disease, medications, alcohol consumption, comorbid conditions, and signs and symptoms of hepatic disease 1.

Key Considerations

• The interpretation of all abnormal liver chemistries must be taken in the clinical context of a given patient, as a normal value does not completely exclude the presence of hepatic disease, and 2.5% of healthy individuals will have an abnormal elevation of a given liver chemistry test by definition 1.
• The evaluation of patients with alanine aminotransferase (ALT) and aspartate aminotransferase (AST) elevations should exclude common hepatic diseases with noninvasive serologic tests, and further testing should be based on the clinical scenario.
• If markedly elevated and/or persistent ALT and AST levels are noted, or if significant symptoms or evidence of chronic or decompensated liver disease are present, a more expeditious and complete initial diagnostic evaluation is typically warranted 1.

Clinical Approach

• Trends over time are often more valuable than isolated values, so comparing current results with previous tests when available is essential.
• Laboratory errors can occur, so unexpected results should be verified before making major clinical decisions.
• When interpreting complex panels, focusing on the most significantly abnormal values first and then assessing how different abnormalities might relate to each other is a practical approach.

Decision Making

• The decision about the need for further diagnostic evaluation and/or the appropriate evaluation can best be made based on the specific clinical scenario of the individual patient 1.
• Chronic ALT or AST elevations (6 or more months) usually warrant additional serologic and radiologic evaluations and potentially a liver biopsy.

From the FDA Drug Label

Adverse Reactions ... Hematologic Eosinophilia (6%), thrombocytosis (5.1%) and leukopenia (2.1%). Less frequently reported (<1%) were anemia, hemolytic anemia, neutropenia, lymphopenia, thrombocytopenia and prolongation of the prothrombin time.

Hepatic Elevations of aspartate aminotransferase (AST) (3.1%) or alanine aminotransferase (ALT) (3. 3%). Less frequently reported (<1%) were elevations of alkaline phosphatase and bilirubin.

Renal Elevations of the BUN (1. 2%). Less frequently reported (<1%) were elevations of creatinine and the presence of casts in the urine.

Investigations Blood creatinine increased (0. 6%).

Altered Laboratory Tests Positive direct Coombs' test, false-positive test for urinary glucose, and elevated LDH

The interpretation of abnormal laboratory values for ceftriaxone includes:

• Hematologic abnormalities: eosinophilia, thrombocytosis, leukopenia, anemia, hemolytic anemia, neutropenia, lymphopenia, thrombocytopenia, and prolongation of the prothrombin time
• Hepatic abnormalities: elevations of AST, ALT, alkaline phosphatase, and bilirubin
• Renal abnormalities: elevations of BUN, creatinine, and presence of casts in the urine
• Other abnormalities: positive direct Coombs' test, false-positive test for urinary glucose, elevated LDH, and increased blood creatinine 2

From the Research

Interpretation of Abnormal Laboratory Values

Abnormal laboratory values can be interpreted in various ways, depending on the context and the specific test results. The following points highlight the key aspects of interpreting abnormal laboratory values:

• Laboratory diagnostic tests are used to screen for disease, confirm or rule out a diagnosis, and monitor patient health 3.
• The interpretation of a diagnostic test result depends on the test's ability to distinguish between diseased and non-diseased individuals, as well as the patient's characteristics and the setting in which the test is used 3.
• Abnormal laboratory results can indicate various conditions, such as anemia, thrombocytopenia, leukopenia, polycythemia, thrombocytosis, and leukocytosis, and require a structured approach to diagnosis and management 4.
• Patients may face challenges in comprehending laboratory test results, including confusion and a lack of understanding of reference ranges, treatment options, and prognosis 5.
• Nurses play a crucial role in assessing laboratory test results, comparing them with physical assessment findings, and incorporating them into the plan and evaluation of care to provide safer and more effective patient care 6.
• A comprehensive approach to laboratory investigation, including first-line, second-line, and third-line testing, can help determine the underlying cause of abnormal laboratory results, such as bleeding symptoms 7.

Key Considerations

When interpreting abnormal laboratory values, the following factors should be considered:

• The patient's medical history and physical assessment findings
• The reference range for the specific test
• The severity and nature of the abnormal result
• The potential underlying causes of the abnormal result
• The need for further testing or consultation with a specialist

Laboratory Test Results

Abnormal laboratory test results can be categorized into different types, including:

• Hematological abnormalities, such as anemia or thrombocytopenia 4
• Electrolyte imbalances, such as hyperkalemia or hypocalcemia 6
• Coagulation disorders, such as bleeding or thrombosis 7
• Metabolic abnormalities, such as hyperglycemia or hypoglycemia 6