Get your Health question answered in 3 easy steps
A Doctor will be with you shortly
Ask a Doctor Now
195 Doctors are Online

Test showed specific gravity 1.005, urine osmolality 106 and blood osmolality 285. Any suggestion?

Aug 2012
User rating for this question
Very Good
Answered by

Practicing since : 1999
Answered : 362 Questions
I had a random urine specific gravity of 1.005 with a urine osmolality of 106 and blood osmolality of 285. Due to the low urine osmolality, the doctor asked me to stop drinking fluids and come back in for the same osmolality tests. I did not drink for 11 hours and then had a Uosm of 380 and Posm of 286. My understanding is that after almost 12 hours of fluid restriction, my Uosm should have been at least 3 times that of my Posm. I am now concerned about diabetes insipidus and yet my doctor says I am concentrating my urine normally. Suggestions?
Posted Thu, 13 Dec 2012 in X-ray, Lab tests and Scans
Answered by Dr. Madhuri Patil 6 hours later
Hi there.

Thank you for your query.

What your doctor says is perpectly alright. What you underwent was water deprivation test and the results are within normal limits for it. Now, if you experience that you are thirsty and after drinking fluids you urinate a lot, then first do fluid input (measure all the water, tea/ coffee, drinks, you consume) and urinary output (measure in a liter bottle) measurements and see what's the result. Specific gravity of your urine is OK.
I went through your past history of diagnosed illnesses. Have you done any prolonged fast test also for the documented hypoglycemia? This is essential to understand what is the reason for your low sugars. If you are overweight, have HbA1c more than 5.7% and have family history of diabetes , then likely you have hypoglycemia before the diagnosis of overt type 2 diabetes. But if that's not the case, then please make sure you mention this to your Endocrinologist and he/ she would certainly put you in systemic investigation series to rule out Insulinoma kind of serious conditions.
In case your urine is very dilute again, then prolonged water deprivation test with series of urine and blood osmolality would be done with MRI of your pituitary gland. But as of now what your doctor said is quite right and just relax about it.
I hope this helps you. Please get back for any related query. Take care.
Above answer was peer-reviewed by
Follow-up: Test showed specific gravity 1.005, urine osmolality 106 and blood osmolality 285. Any suggestion? 13 hours later
Regarding urine: I am thirsty and do urinate a lot (hence the test)....on average every hour and it is not a little bit. With sleep medicine, I get up once a night on average; however, without sleep medicine I get up on average three times per night. Also, this is not my first USG of 1.005. While I know that I more than tripled my urine concentration with the 12 hour fluid restriction, the literature and lab reference on it consistently describe a normal value greater than 850 (although I've seen values as low as 700). Concentrating to 300-500 during an overnight water deprivation is very consistent with partial diabetes insipidus.

Regarding hypoglycemia: I am not overweight, although I could lose about 15 lbs (5'8" and 168lbs) and while my A1c was in the prediabetic range; it has gone down to normal after a year on 25 mg of Januvia (but I've also gained 20lbs since going on the Januvia). I also am in ketosis in a heartbeat and that is when I can feel the worst. One organic acid urine test showed my at 14 times normal ketones in my urine. I did do a 19 hour fast (in the dr. office) and maintained blood sugar. The doctor said that 90% of those with insulinoma become hypoglycemic in the first 19 hours or so, however there is still a 10% chance that I do have an insulinoma but would require longer fasting period. This would require a hospital admission for fasting up to three days. Since the best test for the DI also requires a hospital admission, it would be nice to kill two birds with one stone and do both during one hospital eating and no drinking and see what happens with both.

I also find it very strange that I have to work so hard to maintain blood sugar and hydration....two very primary functions of life....I've always said it is like I have to have the break and gas pedals on at the same time and any slight shift (too much gas or too much break) and my body goes haywire especially if I add strenuous physical activity to the mix. But dehydration and low blood sugar might explain the constellation of symptoms.
Answered by Dr. Madhuri Patil 40 minutes later

Did your doctor also checked for your AM Cortisol levels? When it is less, people tend to have low sugars.
When you said you also have pineal cyst- how was is diagnosed? did you have symptoms? Though a benign condition most of the times, did your doctor ask you to keep follow up on its prognosis?
Now one rare possibility can be that the cyst size has to do something disturbing your surrounding brain tissues including pituitary gland and causing the DI and hypoglycemic symptoms. This I say only on the basis of theory and you do not need to panic. In that case, you would also have menstrual irregularities.
Get yourself tested for these symptoms by admission in the hospital, you would get very very clear idea. Certainly your doctor would check for serum cortisol level etc during that. It's part of the 'fast test' protocol.
I still believe having hypoglycemia is pre-diabetes condition in your case, where you give history of high ketones. But do not take chance and go for the recommended testing. I would say till that do not go for any strenous physical activity unless it's part of your job and somebody accompanies you.
If your hypoglycemia comes as a part of pre-diabetes in your test, then Januvia is not the right medicine. You should be prescribed some medicine from category- 'alpha glucosidase inhibitor'. Please discuss this with your doctor.
Ketones, can be positive when you are fasting for a long time and in place of sugar, the body uses your fat for generating energy. You cannot have ketones positive all the time, I mean, you wouldn't have been well at all to even write this much on computer. So that test must be when you had bad fasting with bad physical activity.
Anyway, your blood ketones (and not urine ketones) will be tested again during the prolonged (72 hr) fast test.
Please get back to me with your reports or any further query. Thanks.
Above answer was peer-reviewed by
Follow-up: Test showed specific gravity 1.005, urine osmolality 106 and blood osmolality 285. Any suggestion? 1 hour later
Pineal cyst was by MRI and was in response to symptoms of strange muscle activity, weakness, utter fatigue. It is "bilobed, septated pineal region cyst characterized by two adjacent cystic components enhancing peripherally following contrast administration...2.0 (A-P) X 1.0cm (craniocaudad) X 1.1cm (lateral). No rounded or solid enhancing components are seen. Although it rests on the anterior surface of the tectal plane, there is no abnormal dilation of the lateral and third ventricles. Stable MRI appearance of benign appearing, but large pineal region cyst"

I had it MRI'd a year later, two years after that and will go for a 5 year (hopefully final) in XXXXXXX 2014. It has been essentially unchanged from 2005 to 2009. Note: I have found a medical article "Diabetes insipidus as an early sign of pineal tumor" WWW.WWWW.WW you're "theory", while unlikely, is possible.

Bad fasting is not eating every 2-3 hours, any variation of less food, more activity can put me in it is a struggle to lose weight because I can end up in a high level of ketosis very easily.

Very interesting comment about the Januvia and I will follow up with her. I don't know about menstrual irregularities as I've been on continuous birth control for the endometriosis (sp? norethindrone 2.5 mg). However, I go off of it about once a year, wait for a period and then go back on it. I did notice something strange after having been on the Januvia....the next time I went off the BC, it took three weeks for a period (I noticed ovulation about a week after stopping the BC and then two weeks after that I had the shortest and lightest period of my life with virtually no cramping (in contrast to long, heavy and extremely painful, i.e. 4 ibuprofen every four hours for 6 days). This was so fascinating to me that I waited another full month before going back on the BC so I could experience another period and see if it was the same easy period and it was....down side was extreme breast tenderness for three of the next four weeks.

I appreciate your feedback. I guess I just have to go advocate for myself with my endo regarding the DI or find another endo.
Answered by Dr. Madhuri Patil 17 minutes later

Please let me know once your tests are done.
Very interestingly, the anti-insulin hormones which cause ketosis are supposed to prevent hypoglycemia. But in your case not a prolonged fast but something else is causing the ketosis.
Wish you all the best.
Above answer was peer-reviewed by
Share on Facebook
Share on Twitter
Share on Google+
Question is related to
Diseases and Conditions
Medical Topics

The user accepted the expert's answer

Ask a Radiologist

© Ebix, Inc. All Rights Reserved.
All the information, content and live chat provided on the site is intended to be for informational purposes only, and not a substitute for professional or medical advice. You should always speak with your doctor before you follow anything that you read on this website. Any health question asked on this site will be visible to the people who browse this site. Hence, the user assumes the responsibility not to divulge any personally identifiable information in the question. Use of this site is subject to our Terms & Conditions
Already Rated.
Your rating:

Ask a Doctor