Differential diagnosis of hypocalcemia are : 
-acute stage of pancreatitis
-renal failure 
-hypoparathyroidism 
-hypoproteinemia
-malabsorption syndrome 
​-osteomalacia of vitamin D deficiency or resistance to vitamin D

Differential diagnosis of raised serum amylase are : 
-intestinal obstruction 
-salivary gland tumors
-pseudocyst of pancreas
-perforated peptic ulcer
-acute pancreatitis 

Differential diagnosis of low ceruloplasmin are : 
-fulminant hepatic failure 
-malabsorption syndrome 
-protein losing enteropathy 
-severe chronic liver failure 
-Wilson's disease

Differential diagnosis of alpha feto protein are : 
-embryonal tumor of the testes 
-hepatoma
-hepatoblastoma
-ataxia telangiectasia
-acute viral hepatitis
-chronic viral hepatitis
​-epithelial carcinoma of the foregut

Differential diagnosis of gynecomastia are : 
-hemochromatosis
-lepromatous leprosy 
-cirrhosis
-Klinfeelter Syndrome 
-myotonic dystrophy 
-testicular atrophy 
-males at puberty 
-estrogen secreting tumor of adrenal gland
-African Human Trypanosomiasis
-drugs - digitalis, reserpine, spironolactone, cimetidine, estrogen for prostate cancer, alpha methyldopa and busulfan
-hyperthyroidism 
-lymphoma
-leukemia
-hepatoma
-large cell carcinoma, adenocarcinoma ( bronchogenic carcinoma) 

Differential diagnosis of hyperkalemia ( intracellular to extracellular potassium shift ) are : 
-insulin deficiency 
-acidosis
-heavy exercise
-succinylcholine
-hyperkalemic periodic paralysis
-digitalis intoxication 
​-beta blocking agent 

Differential diagnosis of pseudohyperkalemia are : 
-thrombocytosis
-leukocytosis
-in vitro hemolysis
​-torniquet use 

Differential diagnosis of hypernatremia ( loss of water due to excess in sodium) are : 
-peritoneal dialysis
-skin loss ( burns)
-sweating 
-drugs - vinblastine, colchicine, amphothericin B, methoxyflurane, sulfonylureas, alcohol, lithium, diuretics and phenytoin
-hypokalemia
-decreased intake of protein 
-hypercalcemia
-excessive use of diuretics
-prolonged excessive intake of water
-multiple myeloma
-Sjogren Syndrome 
-sarcoidosis
-amyloidosis
-congenital nephrogenic diabetes insipidus 
-sickle cell trait
-sickle cell disease
-vomiting
-intestinal fistula
-post hypophysectomy
-trauma to the head
-Wegener Granulomatosis
-tuberculosis
-histiocytosis
-syphilis
-neoplasm 
-infection of the central nervous system 
-Sheehan Syndrome 
-aneurysm 
cerebrovascular accident
-osmotic diuresis
-post obstructive diuresis
-partial obstruction of the urinary tract
-mannitol 
-infant's formula
-tube feeding 
-diuretic phase of acute renal failure
-medullary cystic disease
-polycystic disease
​-chronic renal failure 

Differential diagnosis of hypernatremia ( excessive intake of sodium) are : 
-iatrogenic administration of sodium such as sodium bicarbonate ( in cardio pulmonary resuscitation) or treating lactic acidosis. 
-deliberate or accidental ingestion of large quantities of sodium
-drowning or ingestion of the seawater
-excessive glucocorticoids or mineralocorticoids due to ectopic ACTH production, Cushing Syndrome and primary aldosteronism 

Differential diagnosis of hypernatremia ( due to pure water loss) are : 
-increased insensible loss
-hypothalamic lesions ( impaired thirst drive)
-coma, infancy, dementia - inability to swallow or obtaining water