Blood test results show high bun and creatinine levels explained

What does the blood test results of both high BUN and creatinine levels means?
We determine the result by take in account the BUN to creatinine ratio:
Normal Bun to creatinine ratio should be 1:10 up to 1:20, above this normal range is considered a nephritis and a confirmation by additional tests should by carried by the laboratory to confirm How the inflammation of the kidney is?
So let’s explain the normal ranges and the abnormal values in the box to best understand your lab results of kidney function tests.
What is blood urea?
When food is digested in the body, the proteins in the end turn into two compounds are urea and ammonia may nominate sometimes non-nitrogenous compounds.
Urea is end cracking proteins and nucleic acids in the body which is a toxic substance must be disposed of the body and cleans the blood of them.
What happens if the proportion of urea in the blood?
Urea ratio may not exceed the pathogenesis reasons, but is due to increased eating large amounts of protein in their daily meals.
Urea may increase when the water level less in the blood due to extreme thirst or hunger which called Dehydration.
All of these reasons are non-pathogenesis but in the end show symptoms increase of urea in the blood, such as itching, skin allergies and blood poisoning or so-called Azotemia.
Urea not accurate measurement of kidney functions because urea level may be increased due to dietary reasons as mentioned above.
What is BUN?:
Ancient scientists were measuring level urea in the blood by measuring the amount nitrogen in blood but doctors still rely upon as an accurate measurement of proportion of blood urea
What is creatinine?
Creatinine is a waste biological product which the body system designed to eliminate it from the blood which may be called clearance process.
Measuring creatinine level in the blood is a test which represents the kidney function, why is creatinine serum level showing the functionality of the kidney?
It is from the fact that the creatinine completely eliminated by the body from the circulation, the kidney is the exhaust of the body wastes, so that Kidneys are the Responsible organ of the human body and most of the animals for a job out toxins and unwanted waste from the blood after they have led function in the circulatory system.
Kidneys Getting rid of from all creatinine that contains blood, which passes them through the circulatory system, and therefore it to make sure that the kidneys operate efficiently enough to measure the proportion of creatinine in the blood, which tell us how efficiently the kidneys to get rid of the rest of the toxic compounds and waste unwanted, and therefore the level of creatine in the blood of the patient can create measure of overall efficiency,
Clinical significance of the creatinine and Bun used to identify the health of kidneys as:
Normal serum creatinine Level:
In men is 0.9 up to 1.3 mg/dl (80 – 115 µmol/L)
In women is 0.5 up to 1.2 mg/dl (53 – 97 µmol/L)
Normal blood urea results:
From 20 – 45 mg/dl (100 – 160 mol/L)
Plasma urea to serum creatinine ratio is:
It is range from 12 – 20 mg urea/mg creatinine (49 – 81 mol urea/mol creatinine)
Normal Bun level is:
A normal range for blood urea nitrogen is generally 8 to 24 mg/dL for adult men (2.86 to 8.57 mmol/L) and 6 to 21 mg/dL (2.14 upto 7.50 mmol/L) for adult women.
Norma Bun to creatinine ratio: is 10:1 up to 20:1
This normal creatinine and BUN test result which indicates efficient kidneys function and thus healthy kidneys.
Note that the any high level in creatinine level followed always by the same highness in Urea and Bun levels
A high serum creatinine level is a gradient measurement which each elevation in the Creatinine in blood means a kidney inefficiency degree as following:
Interpretation of many elevated levels of Creatinine and BUN levels?

  1. Serum creatinine level from 1.5 mg/dl upto 2.5 mg/dl and blood Urea from 45 mg/dl up to 100 mg/dl and high BUN results will be 21 – 47 mg/dl: Which result when kidney inefficient due to a criterion called nephritis (i.e. inflammation of the kidney) which is a recoverable, nephritis results from long medication with bee stings, long term medication by penicillin’s, post-SLE, or high glucose levels for long time .Nephritis causes the inflammation of the kidneys for short time and elevates the creatinine level in the blood up to 2.5 mg/dl, but this level is recoverable and you can medicated not so long.
  2. Blood test results that show a Plasma creatinine level more than 2.5 mg/dl (1000 µmol/L) is a critical stage and you should be headed to fast medication because creatinine level above the nephritis level may be indicate a renal failure development.
  3. What does creatinine 10.0 mg/dl and BUN 95 mg/dl?  It is may be a renal failure of a developed stage and should be confirmed by a confirmatory tests which affirm the kidneys conditions, which the kidney filed or not yet.

What is the test to confirm renal failure and high creatinine levels?

  1. Protein in 24 hour urine: is a confirmatory test for nephritis.
  2. Creatinine clearance test: by comparing two samples one from the blood and another sample from the patient’s urine at the same day.
  3. GFR: which indicate the renal glomerular filtration rate; if GFR test is high the kidney is not healthy at all.
  4. NaE test: It is a clearance or Sodium elimination rate from the blood.

Recommendation for high Bun and creatinine levels results:

  1. Repeat tests at another Laboratory, to be reassured that the high results not by technical errors or so called False Positive results.
  2. Do not be scared until you do confirmation tests as I mentioned above.
  3. Do general checkup examination if no reasons suspected.

Understand the difference please:
Renal inflammation or nephritis is indicated by moderate elevation in creatinine level up to 2.5 mg/dl and can be for non-pathogenesis reasons which medicated by lowering proteins intake in the dietary or drink more water when be dehydrated, nephritis may be secondary to long term medications or hyperglycemia, so the kidney efficiency is recoverable, do not worry.
Renal failure is a slow criteria developed after kidney inflammation for long time and started as acute failure which creatinine less than 6.0 mg/dl, acute failure may be nor treated by dialysis and could be medicated as nephritis, but chronic nephritis is developing chronic renal failure in which creatinine will be higher than 7.0 mg/dl up to 20mg/dl or higher, so that the dialysis or even transplantation may be the best solution, as your doctor.
For more help in these tests you can leave a comment with your blood results.

Dr.Megan Ralf

A Medical laboratory Scientist who devoted his life to medical and laboratory sciences, writes his everyday expertise dealing with various pathological conditions through laboratory diagnosis of different body fluids, also participating in many workshops for first aids, infection control, and urgent care. Also Dr Megan Ralf coaching many medical teams.

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