THM1) In case of acute epigastric pain of 4 days, doing serum lipase is better than serum amylase as amylase normalizes by 4 days and lipase can stay abnormal for 14 days. Also, Lipase is more specific for pancreatitis.
THM2) CBC is enough as a cheap screening test for siblings of Thalassemia minor patient. Any sibling with a low MCV then should get a haemoglobin electrophoresis done.
THM3) High cholesterol, high LDL, low Sodium, high MCV, high CPK can all occur due to uncontrolled hypothyroidism. One must achieve euthyroid state before deciding on statins.
THM4) If you are allowed only two tests out of T3, T4, TSH and ESR in case of suspected viral thyroiditis, you can do TSH + ESR or T4 + ESR. T3 is unimportant. ESR is very sensitive.
THM5) You can avoid doing G6PD in an extremely poor patient with vivax malaria before starting primaquine-
- if patient is female
- If patient has taken primaquine in the past without any side effects.
THM6) CRP rises within hours of onset of inflammation or infection and falls quickly once treatment is instituted. ESR rises slowly and falls equally slowly.
THM7) After starting anti-thyroid medicine in recently diagnosed case of hyperthyroidism with high T3, T4 and low TSH, TSH normalises several weeks after T3/T4 normalise. Hence dose uptitration is not based on low TSH levels.
THM8) The diagnostic value of anti TPO antibodies is greatest in hypothyroidism especially because it can guide therapy in subclinical hypothyroidism.
THM9) If a patient comes with altered sensorium with serum sodium 124 mg% in a K/C/O trigeminal neuralgia, suspect drug carbamazepine or oxcabazine as the cause of hyponatremia.
THM10) Total cholesterol can be correctly measured even in non-fasting state. Alcohol on previous day can raise triglyceride levels.
THM11) Rapid urease test for H.pylori requires upper GI endoscopy. Urea breath test is nearly 100% sensitive and specific for H.pylori.
THM12) Clenching of fist plus a venous tourniquet during phlebotomy (blood collection) can significantly raise serum potassium level due to hemolysis and release of potassium from RBCs into serum.
THM13) Adenosine deaminase has 90% sensitivity and 85% specificity for diagnosing TB in serous effusions like pleural effusion / ascites/ pericardial effusion. It is less useful in TB meningitis.
THM14) Excess alcohol can cause macrocytosis (high MCV) without anaemia. If MCV is high in a hypothyroid, one must suspect pernicious anaemia.
THM15) If a patient has both high PSA and alkaline phosphatase, suspect prostate cancer with bone metastases.
THM16) Troponin T or I and CPK-MB should not be done stat if a patient has retrosternal pain since 1 hour only. CPK –MB and troponins may become abnormal by 3-4 hours of onset of myocardial infarction but usually rise by 8-12 hours. ECG may also take hours but is often abnormal immediately.