Can Herbs Cause High Bun and Creatinine Levels?

My 4 year old maltese had routine blood work done a few months ago. It came back with slightly high bun and creatinine levels, >suggesting that she has kidney problems. We then did a urinalysis and that came back perfect, showing no signs at all of kidney >problems.
She is a very healthy dog, has been on a nutritiously balanced home cooked diet her whole life, never took medications and only had >one set of shots when she was born. I do have her on an herbal supplement which my vet claims can be the cause of the elevated >levels in her blood work. Do you know if that is possible that the herbs are causing that?

The herbal supplement she takes daily has: Alfalfa, Garlic, Spirulina, Kelp, Hops, Papaya leaf, Nettles leaf, and Hawthorn berry powder. BUN or blood urea nitrogen is defined by Tabers Medical Enclyclopedia (1997) as "Nitrogen in the blood in the form of urea, the metabolic product of the breakdown of amino acids used for energy production... the level of urea in the blood provides a rough estimate of kidney function. An increase in the blood urea nitrogen level usually indiactes decreased renal function" and creatinine: "The decomposition product of the metabolism of phosphocreatine, a source of energy for muscle contraction. Increased quantities of it are found in advanced stages of renal disease. It is a normal, alkaline constituent of urine and blood."
By stating that the tests showed "slightly high" BUN and creatinine levels, I am assuming you mean only a point or two above the set range on the lab reports. Did your vet want to conduct further tests, ie: an Xray or ultrasound of her kidneys? Has she ever had higher or close to the high end of range readings before? I would recommend that you have the blood work re-tested in a few months and see if there's any change. Sometimes lab reports can show false positives for a number of reasons or there may be another cause, ie: circulation issues, heart problems, stress, etc. As well, you mentioned your dog is on a homemade diet. High BUN levels can be due to increased protein intake. Has she ever had any problems with urination? In addition, substances such as ascorbic acid (Vitamin C) and glucose can give falsely elevated levels of creatinine. have you been adding vitamin C to her diet?
Regarding your list of herbs, I see no reason to believe they are implicated in increased BUN or creatinine levels. Most of them have diuretic properties but none are specific to the urinary system and should have little impact as far as kidney function goes. Indeed, the use of Hawthorn should improve circulation, the papaya may be of help to her digestion and the rest of the herbs are high in vitamins and minerals, thus supporting her body in a general fashion. I am, however, wondering why you chose this particular supplement. As a nutritional boost? If so, I would question the inclusion of Hops in this formula. I would be interested to hear your response.