A colloid shift on a liver–spleen scan is increased radiolabeled colloid uptake by the spleen relative to the liver, reflecting reduced hepatic reticuloendothelial (Kupffer cell) function with compensatory splenic uptake. It is commonly seen with splenomegaly, portal hypertension (for example, cirrhosis), hypersplenism, or impaired liver function and indicates altered reticuloendothelial distribution.

Liver and spleen scans detect structural and functional abnormalities: size changes (hepatomegaly, splenomegaly), focal lesions (cysts, benign tumors, primary cancers, metastases), abscesses, infarcts, trauma-related bleeding, fatty change and cirrhosis, biliary obstruction, vascular disorders (portal hypertension, thrombosis), and infection or inflammatory processes. They help diagnose, stage disease, plan treatment, and monitor therapy response.

A colloid scan is a nuclear medicine test in which radiolabeled colloid (commonly technetium‑99m sulfur colloid) is injected intravenously and taken up by reticuloendothelial cells in the liver, spleen and bone marrow. It assesses organ size and function, detects focal liver lesions or accessory spleens, and helps differentiate splenic tissue from other masses. The procedure is minimally invasive with a low radiation dose.

A liver–spleen scan typically takes about 1–2 hours overall. After an intravenous injection of a small radioactive tracer there is usually a waiting period of 15–60 minutes for uptake, then imaging sessions commonly last 20–60 minutes. Including arrival, preparation and any post-scan checks, expect the whole appointment to be around one to two hours; in some cases it may take slightly longer.

A colloid shift occurs when plasma proteins move from the vascular space into the interstitium, usually due to increased capillary permeability and altered Starling forces. Common triggers include severe inflammation, sepsis, burns, major trauma or surgery, and prolonged hypoxia; aggressive IV fluids can also dilute plasma proteins. The result is lower plasma oncotic pressure, hypoalbuminaemia and tissue oedema.

Ultrasound is fast, portable, radiation-free and good for assessing spleen size, focal lesions and initial trauma screening (FAST), especially in children or pregnancy. CT provides superior detail, higher sensitivity for small lacerations, active bleeding and complex traumatic injury, and is preferred when precise anatomy or contrast-enhanced evaluation is needed. Choice depends on the clinical question, availability and patient factors.