Diagnosis of CKD Electrolytes, blood urea nitrogen (BUN), creatinine, phosphate, calcium, complete blood count (CBC) Urinalysis (including urinary sediment examination) Quantitative urine protein (24-hour urine protein collection or spot urine protein to creatinine ratio) Ultrasonography Sometimes renal biopsy Chronic kidney disease (CKD) is usually first suspected when serum creatinine rises.