Wisely Choosing the Right Lab Tests


December 11, 2017

Hello and welcome. I am Dr George Lundberg, and this is At Large at Medscape.

Most lab tests that are ordered do not need to be done. The results are either normal, negative, or show no change from the previous test. Why do them? I admit that there may be a positive placebo effect from a normal lab result; even a useful sigh of relief from stress for some people upon learning of a normal result. And there are some very good reasons to order lab tests. Sometimes.

In October 2017, the American Society for Clinical Pathology (ASCP) released its five newest "do nots" for the Choosing Wisely initiative. For background, take a look at my 2014 description of the Choosing Wisely process.

Here are all 20 "do nots" from the ASCP, including the five new ones, at the end.

  1. Do not perform population-based screening for 25-hydroxy vitamin D deficiency.

  2. Do not perform low-risk human papillomavirus testing.

  3. Avoid routine preoperative testing for low-risk surgeries without a clinical indication.

  4. Only order methylated Septin 9 to screen for colon cancer in patients for whom conventional diagnostics are not possible.

  5. Do not use a bleeding time test to guide patient care.

  6. Do not order an erythrocyte sedimentation rate to look for inflammation in patients with undiagnosed conditions. Order a C-reactive protein level to detect acute-phase inflammation.

  7. Do not test vitamin K levels unless the patient has an abnormal international normalized ratio and does not respond to vitamin K therapy.

  8. Do not prescribe testosterone therapy unless there is laboratory evidence of testosterone deficiency.

  9. Do not test for myoglobin or creatine kinase-MB in the diagnosis of acute myocardial infarction. Instead, use troponin I or T.

  10. Do not order multiple tests in the initial evaluation of a patient with suspected non-neoplastic thyroid disease. Order a thyroid-stimulating hormone level, and if abnormal, follow up with additional evaluation or treatment, depending on the findings.

  11. Do not routinely perform sentinel lymph node biopsy or other diagnostic tests for the evaluation of early, thin melanoma because these tests do not improve survival.

  12. Do not routinely order expanded lipid panels (particle sizing, nuclear magnetic resonance) as screening tests for cardiovascular disease. A standard lipid profile includes total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride.

  13. Do not test for amylase in cases of suspected acute pancreatitis. Instead, test for lipase.

  14. Do not request serology for Helicobacter pylori. Use the stool antigen or breath test instead.

  15. Do not perform fluorescence in situ hybridization for myelodysplastic syndrome-related abnormalities on bone marrow samples obtained for cytopenias when an adequate conventional karyotype is obtained.

And the five new statements:

  1. Do not order a frozen section on a pathology specimen if the result will not affect immediate (ie, intraoperative or perioperative) patient management.

  2. Do not repeat hemoglobin electrophoresis (or equivalent) in patients who have a prior result and who do not require therapeutic intervention or monitoring of hemoglobin variant levels.

  3. Do not test for protein C, protein S, or antithrombin levels during an active clotting event to diagnose a hereditary deficiency because these tests are not analytically accurate during an active clotting event.

  4. Do not order red blood cell folate levels at all. In adults, consider folate supplementation instead of serum folate testing in patients with macrocytic anemia.

  5. Do not use sputum cytology to evaluate patients with peripheral lung lesions. Sputum cytology is not effective for evaluating peripheral lesions. For peripheral lesion evaluation, consider alternative diagnostic approaches (eg, image-guided needle aspiration).

Did you get all of that?

For brief but cogent justification for all 20 points, take a look at the ASCP's Twenty Things Physicians and Patients Should Question.

You are a smart and ethical doctor. You do wish to choose wisely. Right?

That's my opinion. I am Dr George Lundberg, At Large for Medscape.


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