19. A urine specimen is tested by reagent strip and sulfosalicylic acid (SSA) to determine whether protein is present. The strip yields a negative protein whereas the SSA results in a reading of 2+ protein. This difference is best explained by which of the following statements?,
a. The urine contained an excessive amount of amorphous urates or phosphates that caused the turbidity seen with the SSA test
b. The urine pH was greater than 8, exceeding the buffering capacity of the reagent strip thus causing a false negative reaction
c. A protein other than albumin must be present in the urine
d. The reading time of the reagent strip was exceeded, causing a false negative reaction to be detected.