I found two spots of blood in my one month old grandson's urine filled diaper. no scratches or chaffing anywhere. seen only once. what could it be?

Let me explain: The two possibilities (since no scratches) are from the rectum or the urine, since there no stool in the diaper, i think the urine is the sources, do urinalysis you will find out if the in the bladder is the sources.

? blood ?: There are some urine crystals that can have a orange to rust color and are often confused with blood. If you kept the diaper, the doc can confirm it as blood with a simple reagent test.A urine can be collected for analysis to see if there is blood originating with the urinary tract. I doubt it.