Evaluation of a Test Index Obtained by Coupling Protein with Specific Gravity of Screening Urine Test

BACKGROUND: The 24-hr urine protein excretion test is regarded as a standard for quantitative urinary protein analysis; however, collection of urine over 24 hr is troublesome and errors may occur during the process. We obtained a test index reflecting diluted or concentrated urine by coupling the results of a simple and rapid routine urine analysis and evaluated its usefulness as a marker that quantitatively reflects the 24-hr urine protein excretion. METHODS: The estimated urine protein-osmolality ratio (Pro/Osm) was obtained by two linear regression equations between urine dipstick protein and natural logarithm of the protein concentration, and between urine specific gravity (SG) and urine osmolality (Osm). Sensitivity and specificity of 'estimated urine Pro/Osm' and the widely used urine protein-creatinine ratio were evaluated for their efficiency in diagnosing pathological proteinuria and nephrotic proteinuria based on 24-hr urine protein excretion. RESULTS: Moderate correlations were noted between protein concentration determined by the urine dipstick protein assay and natural logarithm of protein concentration (r=0.86) and between urine SG and urine Osm (r=0.74). The receiver operating characteristics analysis showed that an estimated urine Pro/Osm value of 0.045 had a sensitivity of 91.1% and a specificity of 88.6% for diagnosing pathological proteinuria, and a value of 0.204 had a sensitivity of 100% and a specificity of 80.4% for diagnosing nephrotic proteinuria. CONCLUSIONS: Coupling the results of urine dipstick protein and urine SG determined by the routine analysis will provide additional useful information that will make the screening of renal diseases more cost-effective.

A Case of Smooth Muscle Autoantibody V Pattern in a Patient with Papillary Thyroid Carcinoma

Smooth muscle antibodies (SMAs) are diagnostic markers for the serological diagnosis of type 1 autoimmune hepatitis. SMA that is restricted to staining of the stomach muscle and blood vessel walls was referred to as "SMA-V". In addition, SMAs are classified into the peritubular (SMA-T) and glomerular (SMA-G) patterns. SMAs are occasionally present in patients with malignancies, but have not yet been reported in thyroid cancer. We came across the first case of SMA positivity in a patient with papillary thyroid carcinoma (PTC). A 31-yr-old male was admitted to our hospital for evaluation of incidentally detected thyroid cancer. He had been diagnosed with PTC based on pathological results following fine-needle aspiration biopsy. The patient underwent total thyroidectomy followed by radio-iodine treatment. The serum levels of AST and ALT were increased before radiotherapy. Tests were conducted for the evaluation of liver disease. SMA was positive at a titer of 1:320, showing positive results for the vessel walls but negative results for the glomerulus and tubules in the kidney (SMA-V pattern). The association of SMA with malignancies and the classification of SMA immunofluorescent subtypes have been previously reported. However, these studies have not clearly established the ability of SMA subtype to predict a specific disease. Therefore, evaluation of an association of SMA pattern with specific diseases in SMA-positive patients may provide additional and useful information for the rapid diagnosis and accurate treatment of patients with autoimmune diseases or malignancies. This case report could serve as a great resource for further studies on SMA.