A Problem in Lab Test Selection

By Ed F.

You have just completed your classroom course in clinical pathology, and are doing your clinical rotations. The first night on call, you have a terrible dream.

In the nightmare, it is late Saturday evening. A man is abandoned in the emergency room by his drinking buddies.

The patient is a middle-aged white male, 6' 0" tall and weighing about 90 lb. He can give no history and is not oriented to person, place, or time. He is shouting "...cockroaches... dancing cockroaches... pink elephants and rats all over me..." and struggling with creatures no one else can see. At one point he shouts, "I'm having a heart attack!" He also has a fever and tachycardia, is sweating profusely, and has two large, nonreactive pupils. You easily recognize delirium tremens.

In addition, the patient shows obvious marasmus, a barrel chest, slight gynecomastia, a large, smooth, hard liver edge, a trace of blood in the stool, bilateral hydroceles, tobacco stains on the hands, absent dorsalis pedis pulses with all other pulses strong and symmetric, and onychogryposis of most of the toenails. He goes to your floor.

Chest x-ray shows a few calcified granulomas in both lung fields. EKG shows sinus tachycardia without other abnormalities.

You order a CBC with differential ($10 -- CBC alone costs $5), blood ethanol ($22), glucose-BUN-creatinine-electrolytes ($10), a routine chemical profile (twelve non-stat tests, $18), urinalysis with sediment exam ($18), syphilis tests (RPR for $8 and FTA-ABS for $50), "prothrombin time" ($8), "partial thromboplastin time" ($10), and toxicology screen on urine ($38) and serum ($28).

You also decide to check myocardial enzymes ($14) and CK isoenzymes ($20 -- "before they go down, in case he really is having a heart attack, he does look sweaty and sick..."). Because he looks skinny, you order a hyperthyroid screen (old-style, FTI and T3-RIA -- $24) and "non-super-sensitive" hTSH ($24), and to rule alcoholic pancreatitis in or out, you order an amylase ($9) and lipase ($10) on serum, and tests to calculate amylase-creatinine clearance ratio ($20 total).

The results of these tests are remarkable only for a mild, hypochromic, microcytic anemia, low serum iron, albumin, and cholesterol, elevated liver enzymes suggestive of alcohol abuse, elevated total iron binding capacity, slightly long PT and PTT, blood alcohol 30 mg/dL in the blood, and a trace of diazepam ("Valium") in the blood and urine.

"Because he is bleeding" you order daily CBC's with diffs and forget to cancel the order once he is stable. To further work up his anemia, you request a serum B-12 ($22), serum ferritin ($26), reticulocytes ($6), and haptoglobin ($18).

You take a look at the peripheral smear yourself, and see a few red cells with little air bubbles trapped over their centers (somebody put a coverslip on it). You mistake this for basophilic stippling and order a serum lead ($20), delta-amino levulinic acid ($22), zinc protoporphyrin ($22), delta-amino levulinic acid dehydrase ($20), hemoglobin A-2 ($12 -- "after all, we must consider the diagnosis of thalassemia minor"), and hemoglobin electrophoresis ($20).

You somehow get him to submit to a bone marrow aspiration and biopsy ($100), and order some marrow sent for Philadelphia chromosome ($300 -- "to rule out aleukemic leukemia as a cause for his anemia").

Not wanting to miss some exotic cause of liver disease, you order hepatitis B surface antigen ($18), a "Mono-spot" ($10), quantitative alpha-1 protease inhibitor ($18 -- "after all, he does have bad lungs, too"), anti-mitochondrial antibody ($20), anti-smooth muscle antibody ($20), ceruloplasmin ($20), quantitative immunoglobulins ($35 -- this gets IgG, IgM, and IgA), and urine uroporphyrin and porphobilinogen ($10 together). You order LD (LDH) isoenzymes ($20), and obtain a 5'-nucleotidase ($10) and leucine aminopeptidase ($10) to support your interpretation of the original chemical profile. You order the profile repeated every Monday, Wednesday, and Friday "to follow him".

Because he has a low serum cholesterol and an abnormality of the peripheral pulses, you order a serum lipid profile ($22). As there was blood in his stool, you have three specimens checked for amoebas ($8 each). You also get a serum GGT ($12) because it is considered a good screen for alcoholism.

You order three acid-fast stains and cultures of the sputum ($18 each) to see if the granulomatous disease seen on chest x-ray might be active tuberculosis. You also get an angiotensin converting enzyme ($30), in case the granulomas are really sarcoidosis.

You remember that a hydrocele can be a sign of testicular carcinoma, and order a chorionic gonadotropin ($28), carcinoembryonic antigen ($28), and alpha-fetoprotein ($28). You also order a buccal smear to check for Klinefelter's syndrome ($20).

His leanness prompts you to screen for malabsorption with a serum carotene ($16) and a d-xylose test ($20), and to rule out Addison's disease you get an ACTH ($64), 24-hour 17-ketogenic steroids ($18) and 17-ketosteroids ($18), and stimulated serum and urine cortisols ($22 each, plus $40 for the ACTH you injected). While you are thinking of steroids, you recall that many alcoholic patients have elevated serum aldosterone, so you check that, too ($65). A potassium hydroxide preparation of a piece of his toenail is also ordered ($6).

You treat the man's DT's with chlordiazepoxide, phenobarbital, and phenytoin, and order daily blood levels of each for seven days ($26 per test for chlordiazepoxide, $30 per test for the other two combined).

As he becomes more lucid, he complains that he has been unable to work for thirty years because of low back pain. ("The bastards won't give me compensation, everyone is against me, you doctors don't know a @#$% thing!") So you order HLA-B27 ($50), rheumatoid factor ($8), lupus prep ($12), fluorescent anti-nuclear antibodies ($18), anti-native DNA (Crithidia, $40), anti-Sm ($40), anti-streptolysin ($12), acid phosphatase ($10 -- "to check for metastatic prostate cancer"), and serum and urine protein electrophoresis ($16 each -- "to look for plasma cell myeloma, because bone marrow aspiration can miss it"). When the serum protein electrophoresis comes back with a low albumin and what looks like a polyclonal gammopathy with a beta-gamma bridge, you order a serum immunoelectrophoresis ($36).

Time is speeded up in your dream. The gastroenterologist endoscopes the patient on the third hospital day and sees a hemorrhagic gastritis of the sort that is common in alcoholics. On the twelfth hospital day, the patient sees you approaching with equipment for lumbar puncture and gastric analysis, and escapes out the front door, never to return.

A review of the lab data you have generated shows no reason to think this patient had any illnesses other than alcoholism with malnutrition, early cirrhosis, delirium tremens, and hemorrhagic gastritis, plus bilateral hydroceles, a mixed fungus infection of the toenails, and congenital absence of the dorsalis pedis pulses.

Then the pathologist shows you the lab bill for $4500, and asks you to pay it. You wake up drenched in icy sweat. (Lab charges and habits are from 1983.)


1. Which lab tests did you really need?

2. Which other tests were reasonable choices? (Not everyone will agree, but some choices are much better than others.)

Ed's Pathology Notes
Ed's Autopsy Page
Prayer Request

Ed's Pathology Review for USMLE I

New visitors to
reset Jan. 30, 2005: