What is Urinalysis MSCC?
MSCC stands for Midstream Clean-Catch collection, a urine specimen collection technique where the patient cleanses the perineal area, begins urinating into the toilet, then collects 10-20 mL of the midstream portion in a sterile container without stopping the urine flow. 1, 2
Collection Technique Details
For Female Patients
- Cleanse the perineal area with soap and water or antiseptic wipes, wiping front to back with a fresh wipe for each stroke 2
- Separate the labia and keep them separated throughout the entire collection process 2
- Begin urinating into the toilet, then without stopping the stream, collect 10-20 mL of midstream urine in the sterile container 2
For Male Patients
- Cleanse the glans penis with an antiseptic pad before voiding 1, 2
- Retract the foreskin if uncircumcised 2
- Void the first 100-200 mL into the toilet, then collect 10-20 mL of midstream urine 1, 2
Contamination Rates and Diagnostic Accuracy
MSCC with cleansing significantly reduces contamination compared to collection without cleansing (7.8% vs 23.9% contamination rate). 1, 2
Comparison to Other Collection Methods
- MSCC with cleansing: 7.8-27% contamination rate 1, 2
- MSCC without cleansing: 23.9-32% contamination rate 1
- Sterile urine bag: 44-68% contamination rate 1, 2, 3
- Catheterization: 4.7-12% contamination rate 1, 2
- Suprapubic aspiration: 1% contamination rate (lowest) 2, 3
Diagnostic Performance in Children
When compared to suprapubic aspiration (the gold standard), MSCC demonstrates:
Clinical Context and Limitations
Despite widespread recommendation in guidelines, recent research shows that MSCC may not be as effective as traditionally believed. Multiple studies from 2000-2023 found no significant difference in contamination rates between MSCC with cleansing versus simple random void collection in symptomatic women (contamination rates of 28.6% vs 31.5%, p=0.65). 4, 5
Important Caveats
- Written instructions alone do not reduce contamination rates (51.98% with posted instructions vs 51.99% without, p=0.99) 6
- Mobile app-based instructions similarly show no benefit (38% contamination rate in both groups) 7
- Novel collection devices (funnels) and silver-impregnated wipes do not reduce contamination compared to standard technique 8
When MSCC is Appropriate vs When to Use Invasive Methods
For febrile infants <24 months requiring immediate antimicrobial therapy, catheterization or suprapubic aspiration (not MSCC) is recommended due to superior sensitivity (95%) and specificity (99%). 2, 3
Use MSCC for:
- Toilet-trained children and adults with suspected UTI 1, 2
- Outpatient settings where invasive collection is not feasible 2
Use catheterization or suprapubic aspiration for:
- Febrile infants requiring immediate treatment 2, 3
- When MSCC results show mixed flora and clinical suspicion remains high 3, 9
- Non-toilet-trained children when definitive diagnosis is needed 2
Specimen Handling After Collection
- Refrigerate at 4°C and deliver to laboratory within 4 hours 1, 2
- Check temperature within 4 minutes of collection (should be 90-100°F or 32-38°C) 2
- Document appearance and color immediately 2
Interpreting MSCC Results
Contamination is defined as mixed growth of 2 or more organisms or growth of ≥10^5 CFU/mL of non-uropathogens. 1, 3
Signs of Contamination
- Multiple bacterial species (mixed flora) 3, 9
- Presence of epithelial cells alongside bacteria 3, 9
- Growth of skin flora (coagulase-negative staphylococci) at low counts 9