1. Definition: application of a test to an asymtomatic group to estimate probability that members of group will have a disease
2. Diseases for which screening is appropriate:
   1. Have serious consequences
   2. Are progressive
   3. Are treatable and early treatment produces better results than late treatment
   4. Prevalence of detectable preclinical phase is high in the population being screened.
3. Characteristics of Good Screening Tests       See outline "Diagnostic Tests"
   1. Inexpensive
   2. Comfortable enough to be acceptable to patients
   3. Convenient to perform
   4. Reliable (consistent, relatively insensitive to technique of performer)
   5. Valid (sensitivity - few false negatives, and specificity - few false positives, are high)
   6. High positive and negative predictive value, measures which combine test sensitivity and specificity with prevalence in the population being considered
4. Results of an appropriate screening program
   1. For acute diseases, reduced morbidity and mortality
   2. For chronic diseases, reduced severity and/or prolonged remissions
   3. For infectious disease, screening and early treatment may reduce disease transmission, reducing disease incidence
5. Results of inappropriate screening
   1. Exposes patient to risks associated with screening test (eg. radiation exposure from mammography for low risk women under 40 years old)
   2. Exposes patient to risks associated with diagnostic test following positive screening test (eg. prostate biopsy following positive digital rectal exam)
   3. Exposes patient to anxiety associated with positive screening test (PSA, mammography)
   4. Creates unnecessary expense (CA-125 test for patient at low risk for ovarian cancer.)

1. General screening for anyone >45 years of age is now recommended
2. Fasting serum glucose random test very sensitive (but not specific)
3. Abnormal tests may be followed up with glucose tolerance test
4. Consider fructosamine and/or hemoglobin A1c (HbA1c) levels added to glucose level
5. Persons at elevated risk for type 2 DM should be screened earlier
   1. All obese and overweight persons
   2. Strong family history
   3. Chronic use of glucocorticoids
   4. Consider evaluating patients with hypertension (HTN)
6. Incidence of type 2 DM higher in African versus Caucasian Americans [22]
   1. 1.5X higher incidence in men
   2. 2.4X higher incidence in women

1. Low risk cardiovascular profile associated with ~5-10 year increased lifespan [19]
2. Blood Pressure       See outline "Hypertension"
   1. Usually done 2 or more times per year in patients >40 years
   2. Younger patients should have at least one blood pressure per 2 years
   3. Diagnosis of HTN usually requires 3 separate determinations of high blood pressure
   4. Use home monitoring to distinguish true from white coat hypertension
3. Pulse - all patients
4. Electrocardiography (ECG) - patients with significant cardiac risks, preoperative
5. Chest Radiography
   1. Symptomatic evaluation of chest pain
   2. Not useful for routine pre-operative evaluations
6. Cholesterol levels (see below)
7. Carotid Ultrasound       See outline "Cerebrovascular Disease"
   1. All patients with evidence of coronary artery disease
   2. Patients with other vasculopathy
   3. Patients with carotid bruits
8. Abdominal Aortic Aneurysms [15,16]       See outline "Aneurysms"
   1. High suspicion in patients with other cardiovascular disease, particularly HTN
   2. More common in men than women
   3. Physical examination is unreliable [17]
   4. Ultrasound is screening method choice
   5. Repeat ultrasound for aneurysms >3-4cm
9. Attention to all aspects of therapy for patients with cardiovascular disease [9]
   1. Patients should NOT smoke
   2. Alcohol - 1-2 servings of alcohol per day is associated with improved CV outcomes
   3. Weight should be maintained in normal range
   4. Exercise should be strongly encouraged

1. NCEP recommends screening in all patients >25 years of age
2. Possibly in younger patients with multiple cardiovascular risk factors
3. Normal cholesterol level (<200mg/dl) should be followed q5 years
4. Abnormal level should be repeated with complete cholesterol profile
5. Very Low Total Cholesterol
   1. Has been associated with increased risk of cancer, hemorrhagic stroke, trauma [2]
   2. Part of the cancer risk is due to confounding variables: smoking, GI disease, alcohol [3]
6. High Cholesterol is associated with atherosclerosis and other diseases
7. Primary prevention of adverse events in patients with high cholesterol using pravastatin costs $20-35,000 per life year saved [12]

1. Occult blood tests are mainstay of colorectal cancer screening
2. Usually 1 survey per year in all patients >49 years (or >45 years) old
3. At least 3 stool specimens should be surveyed       See outline "Colon Cancer"
4. Biennial occult blood screening reduces death due to colorectal cancer ~20% [6]
5. For any history of rectal bleeding, full evaluation of colon is recommended [8]
   1. Sigmoidoscopy + double contrast (barium/air) enema OR
   2. Full Colonoscopy
6. Majority (~60%) of patients with positive occult blood have uper GI lesions [13]
   1. Many patients with upper GI lesions take aspirin, ethanol, or other NSAIDs chronically
   2. Esophagitis, gastric ulcer, gastritis and duodenal ulcer all found
7. Flexible sigmoidoscopy in asymptomatic persons over age 50 is recommended regardless of stool occult blood results
8. Finding of even small adenomas (<6mm) should lead to further evaluation [7]
9. Positive Occult Blood and Negative Colonoscopy [18]
   1. All patients with positive occult blood and negative colonoscopy had upper endoscopy
   2. Of the 498 asympatomic patients, 67 (13%) had upper gastrointestinal (GI) lesions
   3. Majority of these had peptic ulcer disease (40 patients)
   4. Another 56 (11%) patients had nonbleeding upper GI lesions which led to therapy change
   5. 1% of the patients were diagnosed with cancer (4 gastric, 1 esophageal)
   6. In the 133 patients with anemia (Hb <12-14gm/dL), 39 had significant upper GI lesions
   7. Therefore, upper GI endoscopy should be considered in patients negative for colonoscopy and positive on fecal occult blood testing

F. Urinalysis and Renal Function

1. Urinalysis - all pregnant women; renal patients; symptomatic patients
2. Serum Electrolytes - baseline may be recommended q1-5 yrs
3. Renal Dysfunction - screening BUN and Creatinine; urinalysis for hematuria, proteinuria
4. Hematuria - malignancy evaluation is required

1. Thyroid Dysfunction       See outline "Thyroid Disease"
   1. Any patient with hypertension or tachycardias
   2. Any patient with suggestive symptoms
   3. Screening women over 35 yrs every 5 years with TSH is cost effective [5]
   4. Whether men should be screened with TSH is less clear [5]
   5. Screening all women >50 with a TSH test is recommended (1 in 71 will be positive) [20]
   6. Persons with TSH <0.4 mU/L have subclinical hyperthyroidism
   7. These persons are at increased risk for atrial fibrillation, osteoporosis, and frank hyperthyroidism
   8. Persons with TSH >5 mU/L (>10% of women >60 years) have subclinical hypothyroidism
   9. These persons are at risk for hypercholesterolemia and frank hypothyroidism
2. Hemochromatosis [1,14]       See outline "Hemochromatosis"
   1. Genetic screening of all patients before age 30-40 is not recommended at this time [14]
   2. Current genetic tests have ~85% sensitivity and very high specificity
   3. Functional screening may be warrented:
   4. Hemochromatosis is a common and very treatable disease in early stages
   5. Functional screen consists of ferritin level, iron, and transferrin saturation
   6. Transferrin saturation >60% and/or ferritin >500ng/mL are strongly suggestive
   7. Such patients should be evaluated liver function testing, possible liver biopsy
   8. Women at much reduced risk than men (usually develop disease at later age)
3. Osteoporosis       See outline "Osteoporosis"
   1. Should be considered in all post-menopausal women
   2. Consider in all patients at increased risk
   3. Consider in patients with abnormal fractures
   4. Routine screening with bone densitometry is increasingly recommended

1. Smoking       See outline "Smoking"
2. Alcohol       See outline "Alcoholism"
3. Recreational Drug Abuse
   1. Cocaine       See outline "Cocaine Overdose"
   2. Opiates       See outline "Opioid Overdose"
4. Anabolic Steroids
   1. Particularly in young athletes
   2. Androstenedione available over the counter 300mg/d increases serum testosterone [21]

1. Pulmonary Function Tests (PFTs)
   1. Active pulmonary disease
   2. Smokers with symptoms       See outline "Cancer Screening"
   3. PFTs for pre-op evaluation only in symptomatic patients
2. Chest radiograph - symptomatic screening only, asbestos exposure

1. This is a critical (often overlooked) part of primary care medicine
2. Two questions can cover depression screening about as well as more complex screens
   1. "During the past month, have you often been bothered by feeling down, depressed, or hopeless ?"
   2. During thepast month, have you been bothered by little interest or pleasure in doing things ?"
   3. This test has a fairly high false positive rate (specificity 57%)
3. Positive answers to above questions should prompt further assessment
   1. Additional information about other aspects of life should be assessed
   2. This includes sleep, eating, social and sexual activity, hopes, et cetera
4. Depression is a major problem in primary care (~30% of typical practice)
   1. Screening is considered a standard and essential component of primary care
   2. Failure to detect depression may result in unnecessary diagnostics, treatments, suffering, and even suicide
   3. Majority of managed care organizations require depression screening in primary care
   4. Failure to detect and/or treat depression may have negative medicolegal ramifications

1. Domestic Violence
2. Glaucoma - tonometry for intraocular pressure       See outline "Glaucoma"
3. Breast Implants       See outline "Breast Disease"
   1. No increased risk of breast cancer       See outline "Breast Cancer"
   2. Increased risk of local reactions
   3. Small, questionable increased risk of connective tissue diseases [4]
   4. Systemic lupus incidence was NOT increased in this large study [4]
   5. Main risk was "any connective tissue disease", not any specific disease
4. Melanoma [10]       See outline "Cancer Screening"
   1. Monthly to bimonthly self screening
   2. Help from spouse / significant other
   3. Yearly or semi-annual screening by dermatologist
   4. Special attention to screening in high risk groups       See outline "Melanoma"
5. Hemochromatosis       See outline "Hemochromatosis"
   1. Overall incidence is 0.5-1% in Caucasian populations
   2. Screening with iron levels ± transferrin is generally considered cost-effective
   3. Persons with (mild) chronic elevations of transaminases should be evaluated

References

1. Baer DM, Simons JL, Staples RL, et al. 1995. Am J Med. 98(5):464
2. Neaton JD, Blackburn H, Jacobs DR, et al. 1992. Arch Intern Med. 152:1490
3. Iribarren C, Reed DM, Burchfiel CM, Dwyer JH. 1995. JAMA. 273(24):1926
4. Hennekens CH, Lee IM, Cook NR, et al. 1996. JAMA. 275(8):616
5. Danese MD, Powe NR, Sawin CT, Ladenson PW. 1996. JAMA. 276(8):285
6. Kronborg O, Fenger C, Olsen J, et al. 1996. Lancet. 348:1467
7. Read Te, Read JD, Butterfly LF. 1997. NEJM. 336(1):8
8. Helfand M, Marton KI, Zimmer-Gembeck JM, Sox HC Jr. 1997. JAMA. 277(1):44
9. Merz CNB, Rozanski A, Forrester JS. 1997. Am J Med. 102(6):572
10. Robinson JK. 1997. JAMA. 278(20:1693
11. Whooley MA, Avins AL, Miranda J, Browner WS. 1997. J Gen Intern Med. 12:439
12. Caro J, Klittich W, McGuire A, et al. 1997. Brit Med J. 315:1577
13. Rockey DC, Koch J, Cello JP, et al. 1998. NEJM. 339(3):153
14. Meduri GU, Headley AS, Golden E, et al. 1998. JAMA. 280(2):159
15. UK Small Aneurysm Trial Participants. 1998. Lancet. 352(9141):1649
16. UK Small Aneurysm Trial Participants. 1998. Lancet. 352(9141):1656
17. Van der Vliet JA and Boll APM. 1997. Lancet. 349:863
18. Bini EJ, Rajapaksa RC, Valdes MT, Weinshel EH. 1999. Am J Med. 106(6):613
19. Stamler J, Stamler R, Neaton JD, et al. 1999. JAMA. 282(21):2012
20. Woeber KA. 1999. Ann Intern Med. 131(12):959
21. Leder BZ, Longcope C, Catlin DH, et al. 2000. JAMA. 283(6):779
22. Brancati FL, Kao WHL, Folsom AR, et al. 2000. JAMA. 283(17):2253

See Outlines

• Melanoma
• Breast Cancer
• Breast Disease
• Glaucoma
• Depression
• Pulmonary Function Tests
• Opioid Overdose
• Cocaine Overdose
• Alcoholism
• Smoking
• Osteoporosis
• Hemochromatosis
• Thyroid Disease
• Colon Cancer
• Hypercholesterolemia
• Aneurysms
• Cerebrovascular Disease
• Hypertension
• Diabetes Mellitus Type 2
• Diagnostic Tests
• Cancer Screening
• Routine Prevention

Table of Contents

Topic List

Updated on: May 13, 2000
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