Reference ranges for laboratory test reports are included in the text of ABIM exam questions, as well as a high/low indicator if a patient's test result falls outside the reference range. As is true in practice, interpretation of a particular patient's test result in relation to the reference range depends on the clinical context. For example, reference ranges for tests assessing lipid or glucose metabolism may not be applicable in certain clinical settings; ABIM reference ranges should not be confused with patient-specific targets for such tests.
Laboratory test results in examination questions are followed by their reference ranges, in brackets and italicized.
Serum albumin 4.0 [3.5–5.5 g/dL]
“H” or “L” will be shown if the patient's test result is higher or lower than the reference range.
Serum albumin 6.0 H [3.5–5.5 g/dL]
For laboratory tests in which the reference range varies according to patient characteristics such as gender or age, the range provided will be appropriate for the patient.
For example, for a 45-year-old man:
Hematocrit 39 L [42%–50%]
For a 45-year-old woman:
Hematocrit 39 [37%–47%]
Information on specific studies
The National Cancer Institute advises that there is no specific normal or abnormal level of prostate-specific antigen (PSA) in the blood. Therefore, ABIM is reporting “no specific normal or abnormal level” in place of the reference range for PSA.
The comprehensive metabolic panel contains the following assays: Albumin, alanine and aspartate aminotransferases (ALT and AST), alkaline phosphatase, total bilirubin, blood urea nitrogen, calcium, creatinine, electrolytes (sodium, potassium, chloride and bicarbonate), glucose and total protein.
Unless noted otherwise in examination questions:
- Arterial blood gas studies are done at sea level with the patient breathing room air
- Reticulocyte counts are uncorrected
- Tuberculin skin tests are done with purified protein derivative (PPD) at intermediate strength (5 TU)
- Electrocardiograms are recorded at normal standard and speed
- Lung volumes are determined by body plethysmography
Download the laboratory reference ranges (pdf) that may be used in ABIM exam questions.