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Middle-Aged Woman with Dark Urine


5. Is it possible the protein is a false positive or at least higher than it should be? Should a confirmatory test for protein be performed?


The protein pad uses buffers to keep its pH at 3, and when protein is present hydrogen ions get released from the indicator, changing the pH and therefore the color on the pad. In heavily alkaline solutions, the pH buffer will become overwhelmed and cause a false positive. Also, a large blood result will have an effect on the protein stix even though they normally detect solely albumin. These two factors may account for the elevated protein. In order to make sure there is really protein in the urine, the SSA test should be performed.








A 35 year old woman went to the doctor complaining of fatigue, shortness of breath, and dark urine. Her skin was very pale, and the whites of her eyes were slightly yellow. She reported recently having a sinus infection which was treated with penicillin. Urinalysis results are:

Color
dark red/brown
Protein
100mg/dL (2+)
Blood
large
Appearance
clear
Glucose
negative
Urobilinogen
12.0 EU
Sp. Gravity
1.020
Ketones
negative
Nitrite
negative
pH
8.0
Bilirubin
negative
Leukocyte
negative

Microscopic
amorphous 2+
hemosiderin granules present

Upon receiving the urinalysis results, the physician orders a blood test for haptoglobin which comes back less than 5 mg/dL (reference range = 26-185 mg/dL).




 
  


  



Colleen Carey | Honors Urinalysis | Fall 2005