Osmolality Puns

If serum sodium is low that means the serum osmolality is going to be low. Why do you need to measure serum osmolality to know that?

I've been trying to make the osmolality values in this table make sense for the past two days. My calculations come out close to those that are published here, but they're not spot on and it's really irritating me. I'm not sure if the values in the table were determined empirically or calculated. Can anyone take a look and tell me what's going on here? Also, I think the % sorbitol is supposed to be (w/v), but my osmolality values come out closer to those in the table when I use (w/w).

MW Sorbitol: 182.17 g/mol
MW Tris-HCl: 157.6 g/mol

Thanks!

Table is from here (https://www.axis-shield-density-gradient-media.com/Preparation%20of%20gradient%20solutions.pdf)

https://preview.redd.it/eb322v4mgtk71.png?width=1066&format=png&auto=webp&s=bb9d0fd67325773998eba9f94965de45d758ca56

That one colleague who leaves a pack with 2 tests left in it on the analyser, when you'd have to run 3 levels of QC to use it.
Writing "poor access" on a form when the tube contains approximately 3ul of blood.
Your employer's work/life balance policy.
Emailing the lab manager to enquire if the further education fund is available to anyone other than the doctors.
The "Staff Suggestion" feature on Q-Pulse.
The big list of what test goes in which bottle in the lab handbook, when you can just ring the lab and ask every time.
Plans for the weekend you're on the shadow rota.

I’m in 4th year so revising for end of year exams 😭 Still have no clue how I got through this many years without understanding this concept.

I’m revising SIADH which has just thrown me back to osmolality.

Is osmolality/ osmolarity used in clinical practice? I believe ones used in clinical practice and one is more research based?

Any simple definitions?

Is there a difference between urine/ serum osmolality?

Is osmolality based on levels of electrolytes in general or specific to sodium, potassium, chloride?

Any very simple explanations would be really appreciated :D Or links to resources!

College project, want a device that measures hydration levels inside the mouth (via gumshield)

UW said that during this stage, oliguria occurs, and there is a volume overload state. Ok, makes sense. Then, renal tubular dysfunction results in low urine osmolality, high urinary sodium, and high fractional excretion of sodium. How??

If there was high Na in the urine, and if water followed along - which would cause a low urine osm, how would this be considered oliguria?

Does anyone know the importance of testing the osmolality of buffers? In particular, buffers that will be used in final formulation and diafiltration in protein purification?

Any help will be greatly appreciated!

Everyone seem to comfortably alternate between the two. -_- Could someone please break down what these terms stand for when presented in a question vignette?

According to my knowledge:

Osmolality is focusing on water content.

And Osmolarity is focusing on the solute content.

• Age - 43
• Sex - F
• Height - 166cm
• Weight - 66kg
• Race - caucasian
• Duration of complaint - 3 months
• Location - kidneys?
• Current medications - Plaquenil 200mg, Nexium 20mg, Maltofer tab daily
• Any existing relevant medical issues

I have been having a range of problems for some time and my last two blood tests showed increasing reduction in sodium levels and blood and urine osmolality. I am also very low in iron and bordering on anaemic according to my GP. On my last blood test, my urine osmolality was 110 mOsm/kg (I cannot recall what the blood osmolality was), sodium 129 mmol/L and iron was 6 (I don't know if this was for ferritin, hematocrit or haemoglobin). I have been taking iron supplements for 4 months and my iron level has gone from 39 to 6 during this time.

I have been experiencing extreme fatigue, nausea, dizziness (it feels like the room spins around me whether standing or lying down), increased urination (and worse at night), increased bruising with slow recovery from bruises (e.g. one bruise on my leg from October 2018 is still faintly visible). I do not have increased thirst, hunger and my urine is very clear most of the time. I typically drink about 1L water per day, 1 weak milky coffee and 2-3 cups of tea so my liquid consumption is not overly high. I also add salt to foods so I don't think it is from my diet. I have put on 6kg since Christmas though lost 1Kg in the past 2 weeks. There is no reason for the weight gain as I eat a lot of salad/vege, fruits, protein and exercise, and this has been my diet and lifestyle for a long time. I experience pain in my mid back and stomach area, as well as a lot of pain near my groin/bladder area.

Up to this point, I have also been experiencing a range of inflammation in my larger joints (knees, wrists, large knuckles) and I have some swelling/inflammation in my left arm (tissue) for the past 2-3 years that the rheumatologist is unsure of. He has diagnosed me with an "unidentified inflammatory disorder". I have a history of cutaneous vasculitis 5-6 years ago which lead to widespread papular purpura and other nonsystemic symptoms for about 3 years which was managed with plaquenil and steroids. I recommenced plaquenil again 18months ago due to the reemergence of papular purpura and other nonspecific inflammation. It was working well until before Christmas.

I have always had normal inflammatory markers (ESR, c-reactive protein, ANA). I have a referral to a nephrologist however i

Can someone PLEASE clear up these definitions for me D:

Is Tonicity a measure of how much water an ion can attract?

For tonicity, when we say that a solution is hypertonic, are we saying that the solution itself has more ions and less water than another solution?

What is osmolarlity vs. osmolality? I know that they are both measures of concentration but like, what is their definition in layman terms and their units? And does EVERY solute (ex. NaCl, Glucose) act as an osmole?

Can someone offer a ELI5 version? There are times where I feel I understand it but when it comes to explain it myself I can't... Which tells me I don't really do understand it myself. Help?

Is this true? My impression was that RAAS was involved in increased reabsorption of Na+--probably the most important osmole. I also understand that H2O rebsorption is increased. Is there simply a net increase in osmolality in urine? Thanks!!

What's the difference? UW Q's list urine osmolarity but lab values tab is for osmolality. Google doesn't help.

At least from what was drilled into me during lectures, aldosterone doesn't cause any changes in osmolality, just blood volume (versus ADH, which causes changes in both osmolality and volume). So why does hyperaldosteronism cause hypernatremia?? Please help a struggling medical newbie out ; o;

See title. Can anyone explain the difference to me without using the words osmolar or osmoles?

I get that osmolarity is the concentration (of solutes/whatever you're measuring) in a solution. Every google search for osmolality leads me to the exact same definition (or I'm not seeing the subtle difference).

Thank you!

EDIT: Thanks everyone. Much clearer now!

how does the hypothalamus detect changes in extracellular osmolality?

Hello,

For some reason, I just cannot wrap my head around this - I know it's common to prepare pipette solutions slightly hypotonic relative to the extracellular bath solution. However, my advisor and some internet forums have mentioned how this helps with seal formation.

Where I stuck on this is that based on basic concepts of osmotic pressure, you'd actually generate positive pressure against the membrane, as water from your pipette solution moves towards the space of higher osmolality, which seems like it would oppose the seal. How does this help with seal formation? Thanks!

[Learn it, Know it: Osmolality (Lube Science)] (http://sex-ational.com/learn-it-know-it-osmolality-lube-science/)

First off: thanks to sex-ational.com for this article. Is this new info to anyone else?

I'm sure many of you are familiar with advertising for personal lubricants that cite pH balance (vaginal pH is most comfortable when the pH is between 5 and 6 for most women), but have you seen an ad address osmolality?

Other than how lube can be an irritant, there's one ingredient you should probably watch out for, ladies. It's "chlorhexidine gluconate", and anti-bacterial. It's bad news because it kills all your good/healthy vaginal bacteria.

A recent interview with alternet.org featured the wonderful Ellen Barnard, co-founder and co-owner of A Woman’s Touch, which provides products and information for sexual health and pleasure in Madison, WI. The article points out that in the coming year, "As of Jan. 1, 2015, the FDA will require animal testing for personal lubricants. They are not testing to see how effective a product is as a lube, just whether or not it irritates the animals tested." However Barnard wisely notes: "But just because the rabbits don't get irritated doesn't mean you won't.”

A common way to test if something is going to irritate your skin is to patch test on the inside of your elbow, but this obviously isn't the same as it interacting with your mucous membranes.

Have any of you had negative experiences with lubes? I personally find most 'cooling' or 'warming' lubricants to be irritating. I don't condone animal testing, but I'm glad they're being tested more. Thoughts?

Why is the serum osmolality normal in FVD?