A 70 year old woman residing in the nursing home was noted to have amber urine and clay colored stools by one of the nursing aides. Her skin also appeared faintly yellow. A first morning urine sample was collected and a urinalysis was performed.
 

Physical / Chemical Urinalysis Results

color: amber
appearance: clear
specific gravity: 1.030
pH: 5.5
protein: negative
glucose: negative
ketones: negative
bilirubin: small
blood: negative
urobilinogen: 0.2 mg/dL
nitrite: negative
leukocytes: negative
bilirubin crystals (as seen in this photomicrograph)
 

Questions

1. Based on the patient symptoms, which condition is most likely?
  a) nephrotic syndrome
  b) prehepatic jaundice
  c) posthepatic jaundice

2. What could have caused this condition?
  a) gall stones
  b) fibrosis
  c) carcinoma
  d) all of the above

3. What could account for a negative or decreased bilirubin result if bilirubin was actually present in the urine?
  a) improper storage
  b) drug induced color changes
  c) beets

4. Why would a blood test be helpful in this case?
  a) to test for unconjugated bilirubin
  b) to check the platelet count
  c) to test for conjugated bilirubin
  d) all of the above