Many chiropractors, even [those that are] well trained, avoid ordering laboratory tests. Sometimes this is because laboratory testing is outside of their comfort zone; sometimes it is because of reimbursement issues. However, a reluctance to order laboratory tests does not preclude one from the responsibility of knowing which tests to order, and when it is appropriate to order them.

An aspect of laboratory diagnosis that is beginning to get more attention in the world of preventive health care is that of wellness screening. In wellness screening, we test asymptomatic patients who are basically healthy. Tests are chosen that screen for the presence of prevalent diseases that can be detected before clinical findings develop. These diseases are treatable (not necessarily curable). Delay in treatment results in harmful and sometimes preventable consequences¹. Timely detection and subsequent treatment will at the very least delay eventual problems.

Many medical associations, organizations and task forces have published guidelines for prudent wellness screening. There is no total consensus among these groups. However, the following chart summarizes my recommendations based upon the varied groups whose guidelines I reviewed². (NOTE: You will find a more detailed explanation of these recommendations following the chart below).

CHOLESTEROL
Most of the guidelines reviewed recommend serum total cholesterol as a basic screening tool. The optimal level is <200 mg/dL (<5.2 mmol/L), although many holistic practitioners like myself advocate a more rigid 180 mg/dL (4.65 mmol/L). The National Cholesterol Education Program (NCEP) suggests also looking at both the LDL and HDL cholesterol levels. The optimal levels for these lipoproteins are LDL <100 mg/dL (<2.59 mmol/L), HDL >40 mg/dL (>1.03 mmol/L) in men, and HDL > 50 (1.3mmol.L) in women. Elevated LDL cholesterol is considered a positive risk factor for coronary artery disease. Elevated HDL cholesterol is considered a negative risk factor. I recommend doing all three tests for the purpose of wellness screening. If the levels are optimal the tests are repeated in five years. Test should occur after a 12 hour fast. Abnormal tests should be confirmed by at least one additional measurement within 8 weeks. I suggest becoming familiar with NCEP's website which is www.nhlbi.nih.gov.

FASTING PLASMA GLUCOSE (FPG)
Type 2 diabetes mellitus (formerly called non-insulin diabetes type II) is a major public health concern. Its prevalence is increasing, and it is appearing at earlier ages. The reason for this is obvious; Americans eat unhealthy diets and they are overweight, including our younger generations. The American Diabetes Association (ADA, www.diabetes.org/main/application/commercewf) recommends screening for diabetes commence at the age of 45 years using a single fasting plasma glucose assay. A normal FPG level is <110 mg/dL (<6.1 mmol/L). An individual is considered diabetic if the FPG is ³126 mg/dL (³7.0 mmol/L). The ADA recommends the test be confirmed on a separate day. If the test result is normal, it is repeated in three years. If an individual is a member of a high-risk ethnic population (African American, Native American, Asian, or Hispanic) or is a first-degree relative of a diabetic, screening should commence as early as age 30 years.

FECAL OCCULT BLOOD TEST (FOBT)
Colorectal cancer is the third leading cause of cancer-related deaths in both males and females in the USA. Most cancerous and some pre-cancerous lesions bleed. Therefore, detection of these lesions by finding hidden (occult) blood in the stool (termed melena) is the least invasive and most cost-effective method of screening. A three-card FOBT kit must be used. These kits require three specimens collected on three consecutive days, thus increasing the probability of finding blood if bleeding is occurring. Also, a specific diagnostic diet must be followed for four days prior to and during testing. The test kits always provide exact details about the diagnostic diet. Screening via FOBT commences at the age of 50 years for average-risk men and women. This initial screening should also be accompanied by flexible sigmoidoscopy to 65 cm. The FOBT is repeated yearly. The sigmoidoscopy is repeated in 3-5 years. Screening commences no later than age 40 years for an individual who is a first-degree relative of a patient with colorectal cancer. A good website for FOBT is from the Cleveland Clinic in Ohio; ww.clevelandclinicmeded.com/ihpage/ihpage2/fecal.htm.

PAP TEST
Cervical cancer can be detected via the Pap test which is part of a yearly pelvic examination. Testing commences once the patient becomes sexually active, but no later than age 18 years. Many women-healthcare practitioners recommend yearly testing thereafter. However, some current thinking is testing can be performed every 2 years if a woman is monogamous for at least three years in which she has a normal Pap in each of those years.

PROSTATE SPECIFIC ANTIGEN (PSA)
Prostate cancer is the most common cancer of men. Transrectal ultrasound- guided (TRUS) biopsy of the prostate is the "gold standard" diagnostic test, but it is impractical as a screening test. Screening via a combination of a digital-rectal examination (DRE) and serum PSA seems to be the consensus recommendation. However, the use of PSA in asymptomatic individuals is quite controversial. The following website is just one illustration of this ongoing controversy. www.prostatepointers.org/ww/psamark.htm#acp) The goal of screening via DRE and PSA is the early detection of organ-confined (not spread beyond the gland) cancer. Once the cancer spreads beyond the gland, the prognosis is poor. Currently, screening commences at age 50 years, and is repeated yearly. Screening should commence at the age of 40 years for an individual who is a member of a high-risk ethnic population (African American) or is a first-degree relative of a prostate cancer patient. A positive DRE regardless of PSA level results in a biopsy. Depending upon which expert-opinion one reads, the optimal PSA level is <2.5 ng/mL for men under the age of 49 years³, and <3.0 ng/mL for ages 50 years and beyond. No biopsy is required at the optimal level, unless it is an increase of >0.75 ng/mL from the previous year. A level of ³10.0 ng/mL is an absolute indication for a biopsy. The screening PSA is a "total" PSA. PSA circulates in two forms; complexed (primarily to protease inhibitors) and free. When the screening PSA is between 2.5 (or 3.0)-10.0 ng/mL, a percent free PSA (% f-PSA) is reflexively performed. A significant decrease in this fraction (malignant cells proportionately produce less free PSA) aids in determining the need for a biopsy. I recommend looking at the website of one of the experts on this subject, William Catalona, MD who performed prostate surgery on New York Yankees manager Joe Torre: www.drcatalona.com.

TRANSFERRIN SATURATION (TSAT)
Also termed % saturation of transferrin (%sat), TSAT is used to screen for a potentially life-threatening inherited disorder called hemochromatosis, or iron overload. In this disease, an unusable form of Iron called hemosiderin is deposited into multiple organs causing irreversible damage. The most common complications include hepatic, pancreatic, and cardiac insufficiency, and hypogonadism⁴. The condition is rarely clinically evident until after the age of 50 years. Hence, it is recommended that all adults (>30 years) be screened once for this condition no later than at age 50 years. A fasting TSAT in excess of 60% is considered positive, and should be repeated at least once. A serum ferritin is often used to confirm these results. Tissue biopsy is then required to establish a definitive diagnosis. There are many websites about this condition, but this one is from the CDC; w.cdc.gov/nccdphp/dnpa/hemochromatosis/.

CONCLUSIONS
Chiropractors treat many patients who should be prudently and periodically screened for certain diseases. Many of our patients are not receiving such recommendations from their other health care providers. Sometimes we are our patient's only doctors. As primary care providing, portal-of-entry practitioners, chiropractors need to be certain our patients are receiving the best preventive care possible. Wellness screening should become a regular component to the care we provide.

^* This article was written by Dennis Hoyer, MT(ASCP), DC, Associate Professor of Clinical Sciences Western States Chiropractic College.
¹ Speicher, CE: The Right Test, A Physician's Guide to Laboratory Medicine, 3rd edition, Saunders, 1998.
² Guidelines from: American College of Physicians; Canadian Task Force on the Periodic Health Examination; College of American Pathologists; National Cholesterol Education Program; Ohio State University Health Plan; US Preventive Services Task Force; Washington State Clinical Laboratory Advisory Council.
³ Barry, MJ: Nonpalpable prostate cancer in Diagnostic Strategies for Common Medical Problems, 1999, American College of Physicians, Philadelphia, Pennsylvania.
⁴ Tierney, LM et al: Current Medical Diagnosis and Treatment 2002, McGraw Hill, 2002.