This section shows how diagnostic tests can be used in differential diagnosis and difficult diagnostic challenges. Material is presented in algorithmic forms, and contents are listed in alphabetical order by condition.
Abbreviations used throughout this section include the following: N = Normal; ↑ = Increased or high; ↓ = Decreased or low.
Each algorithm uses the following conventions:
ACID–BASE DISTURBANCES: DIAGNOSTIC APPROACH
ACID–BASE DISTURBANCES: Diagnostic approach. GI = gastrointestinal.
ADRENAL MASS: DIAGNOSTIC EVALUATION
ADRENAL MASS: Diagnostic evaluation. CT = computed tomography; DHEA-S = dehydroepiandrosterone sulfate; 17-KS = 17-ketosteroids; MRI = magnetic resonance imaging.
ADRENOCORTICAL INSUFFICIENCY (HYPOCORTISOLISM): LABORATORY EVALUATION OF SUSPECTED ADRENOCORTICAL INSUFFICIENCY (HYPOCORTISOLISM)
ADRENOCORTICAL INSUFFICIENCY (HYPOCORTISOLISM): Laboratory evaluation of suspected adrenocortical insufficiency (hypocortisolism). ACTH = adrenocorticotropic hormone.
AMENORRHEA OR OLIGOMENORRHEA: DIAGNOSTIC LABORATORY EVALUATION FOR AMENORRHEA OR OLIGOMENORRHEA
AMENORRHEA OR OLIGOMENORRHEA: Diagnostic laboratory evaluation for amenorrhea or oligomenorrhea. Primary amenorrhea is defined as the failure of menses to appear by age 16. Secondary amenorrhea is defined as occurring in women who have secondary sexual characteristics, have experienced menarche, and are presenting with consistently absent menses (more than 3 consecutive months). Oligomenorrhea is defined as scanty menses, or menses occurring at intervals of >35 days with only 4–9 menstrual periods in 1 year. Pregnancy must be ruled out before pursuing the testing outlined in the algorithm. APS = autoimmune polyglandular syndrome; CAH = congenital adrenal hyperplasia; E2 = estradiol; FSH = follicle-stimulating hormone; FT4 = free thyroxine; LH = luteinizing hormone; MRI = magnetic resonance imaging; PCOS = polycystic ovarian syndrome; PRL = prolactin; TSH = thyroid-stimulating hormone. (Modified with permission from Gardner DG, Shoback D [editors]: Greenspan's Basic & Clinical Endocrinology, 9th ed. McGraw-Hill, 2011.)
ANEMIA: GENERAL CONSIDERATIONS AND INITIAL EVALUATION
ANEMIA: General considerations and initial evaluation. The initial evaluation of anemia should include complete blood cell count, reticulocyte count and review of peripheral blood smear. G6PD = glucose-6-phosphate dehydrogenase; HE = hereditary elliptocytosis; HS = hereditary spherocytosis; LDH = lactate dehydrogenase; MAHA = microangiopathic hemolytic anemia; MCV = mean corpuscular volume; PK = pyruvate kinase; PNH = paroxysmal nocturnal hemoglobinuria.
ASCITES: DIAGNOSTIC EVALUATION
ASCITES: Diagnostic evaluation. GLU = glucose (mg/dL); HF = heart failure; LDH = lactate dehydrogenase (IU/L); ...