The diagram shows colour boxes from a urine test strip used at a school health screening. The strip was compared with the manufacturer chart after 60 s. A p...
Question 1 Report
The diagram shows colour boxes from a urine test strip used at a school health screening. The strip was compared with the manufacturer chart after 60 s. A person had eaten breakfast containing carbohydrate two hours earlier.
(a) Which substance is indicated by the grey glucose box on the test strip? [1]
(b) State why glucose in urine may suggest that the person has diabetes. [1]
(c) Explain why glucose is normally absent from the urine of a healthy person. [2]
(d) Describe one change to the test procedure that would make the comparison with the chart more reliable. [2]
(e) Give one reason why a doctor would not diagnose diabetes using this test alone. [1]
Answer Details
(a) The grey glucose box indicates glucose. [1]
(b) Glucose in urine may suggest diabetes because blood glucose may be above the level at which the kidneys can reabsorb all of the glucose. [1]
(c) In a healthy kidney, glucose is first filtered into the nephron. It is then selectively reabsorbed into the blood from the kidney tubule, so it is normally absent from urine. [2]
(d) To improve reliability, use two suitable procedural controls, such as using the stated timing exactly and repeating the test with another sample. Using a fresh, in-date strip or comparing under the same light conditions are also acceptable. [2]
(e) A doctor needs a confirmatory blood-glucose test; a single urine result can be affected by other factors and is not sufficient alone for diagnosis. [1]
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