Urine routine protein is negative and urine microalbumin is high, the reason is...  

foreword

Routine urinalysis and urine microalbumin testing are commonly used to detect the presence of protein in the urine, and clinicians often prescribe both tests together when assessing kidney dama.

case after

The patient, male, 22 years old, came to the outpatient department of nephrology in our hospital with "systemic lupus erythematosu.

When reviewing the measurement results of urine microalbumin, it was found to be significantly increased, reaching 1812 mg.

Because the sensitivity of urine microalbumin determination is higher than that of urine dry chemical protein determination, it is common sense that the urine microalbumin is slightly elevated and the urine routine protein is negative in the early stage of kidney inju.

Considering the turbidimetric method used for the measurement of urine microalbumin, it was suspected that the increase in urine turbidity caused a false-positive measurement of urine microalbum.

After centrifugation, the sample was tested again on the machine, and it was found that the urine microalbumin test result became negative (9mg/L), which verified that the first test result was a false positive caused by the increase of urine turbidi.

In order to find out what kind of substance the white precipitate is, first observe the precipitate under a microscope and find large crystals:

Unstained, X400 times

Combined with the urine pH value (5), the white precipitate and the observation under the microscope, the possibility of phosphate crystallization is considered to be hi.

case analysis

Urine routine dry chemical method for determination of urine protein adopts the principle of pH indicator protein error, which is simple and fast to operate, and is suitable for health screening and clinical screeni.

At present, the commonly used methods for the determination of urinary microalbumin include immunolabeling method and immunoturbidimetric method, and immunoturbidimetric method is more commonly us.

Although routine urine and urine microalbumin detect the same substance, the sensitivity of urine microalbumin determination is higher than that of urine dry chemical protein determinati.

There are a variety of crystalline substances in urine, and they are generally in a dissolved sta.

Common crystals originate from food, drug and salt metabolism, and can be divided into physiological crystals, pathological crystals and drug crysta.

Summarize

As an inspection worker, the interference factors that affect the test results should be promptly discovered and eliminated in daily wo.

references:

[1] Cong Yulong, Ma Junlong, Zhang Shim.

[4] Shang Hong, Wang Yusan, Shen Zi.

The 4th edition of the National Clinical Laboratory Operation Regulations [.

People's Health Publishing House, 201