Category Archives: Laboratory Medicine

Macrocytic Anemia: The Workup

The workup for macrocytic anemia should include some or all the following: Peripheral blood smear Hypersegmented neutrophils and macroovalocytes → B12 and folate deficiency. Advanced B12 deficiency → pancytopenia. Target cells → chronic liver disease (anemia and thrombocytopenia are also seen). Pseudo-Pelger-Huët cells → myelodysplastic syndrome. For vitamin B12 deficiency Vitamin B12 levels Methylmalonic acid → high in vitamin… Read More »

Chronic Diarrhea: Laboratory Medicine Tips and Tricks

Routine labs can tell you a great deal about your patient’s chronic diarrhea: Potassium: Potassium should, of course, be low in patients with chronic diarrhea. If it is high and the patient has normal kidney function, then your patient may have Addison’s disease, or primary adrenal insufficiency. Microcytic anemia: microcytic anemia suggests anemia of iron deficiency and therefore… Read More »

Hypocomplementemia: Key Points and Mnemonics

You don’t need to memorize which glomerulonephritides are associate with low complement and which are not. Rather, ask yourself one question: does this patient have persistent, aggressive, endovascular, systemic infectious or inflammatory processes? If the answer is “yes,” then the disease is associate with low complement levels. If the answer is “no,” then complement level will be normal.… Read More »

Laboratory Findings in Multiple Myeloma

Multiple myeloma is associated with more laboratory abnormalities than any other disease. Some of the notable ones are: Blood Peripheral blood smear: normocytic, normochromic anemia, macrocytic anemia, rouleaux formation, neutropenia, thrombocytopenia, abnormal plasma cells (15%) High Erythrocyte Sedimentation Rate (ESR) High serum total protein and low albumin/globulin ratio Septicemia: especially from encapsulated organisms, which are normally cleared by… Read More »

How to Solve Triple Acid-Base Problems Quickly in Your Head

Introduction You can solve triple acid-base problems with basic arithmetic and straightforward logic. As an example, let’s work through the following rather classic triple acid-base problem: An afebrile, atraumatic 26-year-old male with no past medical history is brought to the emergency department because of a three hour history of altered mental status, vomiting and vertigo. The physical examination is positive only for somnolence… Read More »

How to Use LDH in Clinical Decision-Making

Introduction Lactate dehydrogenase, or LDH, is a marker of cell breakdown almost anywhere in the body, most notably red blood cells, liver, lungs, heart, brain, and kidneys. Thus, a negative LDH is an extremely useful test result because it tells you that all sorts of things are not going on with your patient. An elevated LDH is also a useful and specific test result… Read More »