Salivary creatinine as a diagnostic tool for evaluating patients with chronic kidney disease.

BACKGROUND: Preliminary studies have shown the potential use of salivary creatinine concentration in the diagnosis of chronic kidney disease (CKD). For saliva to replace serum as a diagnostic tool, studies must be done to determine its effectiveness in the diagnosis and staging of CKD. The aim of the present study was to evaluate the use of salivary creatinine as a safe and non-invasive alternative for identifying patients with CKD. METHODS: A cross-sectional study was conducted at Tygerberg Hospital in Cape Town, on 230 patients, across all stages of CKD. Ethical approval to conduct the study was obtained from the University of the Western Cape Biomedical Research Ethics Committee, and written informed consent was provided by each participant. Saliva and serum samples were collected for creatinine analysis and the correlation determined using Spearman's correlation. Receiver operating characteristics (ROC) analysis was used to determine the diagnostic ability of salivary creatinine. A cut-off value for optimal sensitivity and specificity of salivary creatinine to diagnose CKD with glomerular filtration rate (GFR) < 60 mL/min/1.73 m2 was obtained. RESULTS: Serum creatinine values ranged from 46 µmol/L to 1581 µmol/L, with a median value of 134 µmol/L. Salivary creatinine values ranged from 3 µmol/L to 400 µmol/L, with a median of 11 µmol/L. There was a strong positive correlation (r = 0.82) between serum and salivary creatinine values. Linear regression analysis of serum and salivary creatinine for CKD patients was significant in all CKD stages, except for stage 1. Area under the curve for salivary creatinine was 0.839. A cut-off value of 8.5 µmol/L yielded a sensitivity of 78.3% and specificity of 74.0% for classifying patients as having CKD based on estimated GFR < 60 mL/min/1.73 m2. CONCLUSIONS: The results support the potential of salivary creatinine as a non-invasive diagnostic tool for estimating GFR and identifying patients with CKD.

Penile allotransplantation for penis amputation following ritual circumcision: a case report with 24 months of follow-up.

INTRODUCTION: Ritual circumcision complicated by gangrene is a leading cause of penile loss in young men in South Africa. This deeply rooted cultural tradition is unlikely to be abolished. Conventional reconstructive techniques using free vascularised tissue flaps with penile implants are undesirable in this often socioeconomically challenged group because donor site morbidity can hinder manual labour and vigorous sexual activity might lead to penile implant extrusion. The psychosociological effects of penile loss in a young man are devastating and replacing it with the same organ is likely to produce the maximum benefit. METHODS: We first performed a cadaver-to-cadaver penile transplantation as preparation. After approval from the Human Research Ethics Committee was obtained, we recruited potential recipients. We screened the potential participants for both physical and psychological characteristics, including penile stump length, and emotional suitability for the procedure. A suitable donor became available and the penis was harvested. We surgically prepared the penile stump of the recipient and attached the penile graft. Immunosuppression treatment with antithymyocyte globulin, methylprednisolone, tacrolimus, mycophenolate mofetil, and prednisone were commenced. Tadalafil at 5 mg once per day was commenced after 1 week as penile rehabilitation and was continued for 3 months. We collected on quality-of-life scores (Short Form 36 version 2 [SF-36v2] questionnaires) before surgery and during follow-up and measured erectile function (International Index for Erectile Function [IIEF] score) and urine flow rates at 24 months post transplant. FINDINGS: The warm ischaemia time for the graft after removal was 4 min and the cold ischaemia time was 16 h. The surgery lasted 9 h. An arterial thrombus required urgent revision 8 h after the operation. On post operative day 6, an infected haematoma and an area of proximal skin necrosis were surgically treated. The recipient was discharged after 1 month and first reported satisfactory sexual intercourse 1 week later (despite advice to the contrary). The recipient reported regular sexual intercourse from 3 months after the operation. An episode of acute kidney injury at 7 months was reversed by reducing the tacrolimus dose to 14 mg twice per day. At 8 months after surgery, the patient had a skin infection with phaeohyphomycosis due to Alternaria alternata, which we treated with topical antifungal medication. Quality-of-life scores improved substantially after the operation (SF-36v2 mental health scores improved from 25 preoperatively, to 57 at 6 months and 46 at 24 months post transplant; physical health scores improved from 37 at baseline to 60 at 6 months and 59 at 24 months post-transplant). At 24 months, measured maximum urine flow rate (16·3 mL/s from a volume voided of 109 mL) and IIEF score (overall satisfaction score of 8 from a maximum of 10) were normal, showing normal voiding and erectile function, respectively. INTERPRETATION: Penile transplantation restored normal physiological functions in this transplant recipient without major complications in the first 24 months. FUNDING: Department of Health, Western Cape Government.

The influence of storage time and temperature on the measurement of serum, plasma and urine osmolality.

BACKGROUND: Many clinical laboratories require that specimens for serum and urine osmolality determination be processed within 3 h of sampling or need to arrive at the laboratory on ice. This protocol is based on the World Health Organization report on sample storage and stability, but the recommendation lacks good supporting data. We studied the effect of storage temperature and time on osmolality measurements. METHODS: Blood and urine samples were obtained from 16 patients and 25 healthy volunteers. Baseline serum, plasma and urine osmolality measurements were performed within 30 min. Measurements were then made at 3, 6, 12, 24 and 36 h on samples stored at 4-8℃ and room temperature. We compared baseline values with subsequent measurements and used difference plots to illustrate changes in osmolality. RESULTS: At 4-8℃, serum and plasma osmolality were stable for up to 36 h. At room temperature, serum and plasma osmolality were very stable for up to 12 h. At 24 and 36 h, changes from baseline osmolality were statistically significant and exceeded the total allowable error of 1.5% but not the reference change value of 4.1%. Urine osmolality was extremely stable at room temperature with a mean change of less than 1 mosmol/kg at 36 h. CONCLUSIONS: Serum and plasma samples can be stored at room temperature for up to 36 h before measuring osmolality. Cooling samples to 4-8℃ may be useful when delays in measurement beyond 12 h are anticipated. Urine osmolality is extremely stable for up to 36 h at room temperature.