Technetium Tc 99m mertiatide
The standard tracer for dynamic kidney scans: a technetium-99m complex of a glycine tripeptide that the kidney tubules secrete
Technetium Tc 99m mertiatide, universally called MAG3, is a diagnostic radiopharmaceutical. A hospital radiopharmacy makes it shortly before use by adding radioactive technetium-99m to a kit containing mercaptoacetyltriglycine, a small acylated chain of three glycines that grips the metal. Injected into a vein, it is pulled out of the blood by the kidney tubules and passed into the urine within minutes, and a gamma camera filming the kidneys turns that passage into images and curves of each kidney's function and drainage. It replaced radioactive iodine-labelled hippuran after its US approval in 1990 and is used in infants, adults and kidney transplant recipients.
Manufacturer's recommended dosing (FDA label): 185-370 MBq (5-10 mCi), Single injection per study, Intravenous injection Details ↓
Recommended Dosing
Manufacturer's recommended dosing (FDA label)
From the prescribing information. Other doses studied, if any, are in the full dosing data below.
What is it?
For decades kidney function scans relied on iodine-131 or iodine-123 labelled hippuran (OIH), a compound the kidney tubules secrete almost completely. Iodine-131 gives poor pictures and a high radiation dose for the amount that can be injected, so in the 1980s chemists looked for a technetium-99m agent that behaved the same way. Fritzberg and colleagues built a ligand from mercaptoacetic acid and three glycines, four donor atoms arranged to hold technetium, and called it MAG3. In mice and rats the technetium complex was cleared faster than hippuran and almost entirely by the kidneys, and in ten volunteers its images were clearly better.
MAG3 differs from hippuran in ways that shaped how it is used. It binds more strongly to plasma proteins, stays more within the bloodstream, and is cleared at only about half to two thirds of hippuran's rate. Researchers coined the term tubular extraction rate for its clearance and showed that it correlates closely with hippuran's, so that renal plasma flow can still be estimated from it. Because it is handled mainly by tubular secretion, it gave clearer images than the filtered agent technetium-99m DTPA in transplant patients whose kidney function was impaired.
Its US label covers diagnosis of congenital and acquired abnormalities, kidney failure, urinary obstruction and stones in adults and children, giving split function, renal angiograms and renogram curves. In practice it is the workhorse of diuretic renography for suspected obstruction, especially hydronephrosis in babies, of captopril renography for narrowed kidney arteries, and of scans after kidney transplantation, where a low tubular extraction rate in the first week predicted delayed graft function and later graft loss in a study of 488 recipients. Its limits are well documented too: a scan could not reliably tell rejection from acute tubular necrosis, observers disagree on subtle defects, and sedation or poor kidney function can produce misleading curves.
Radiation dose is modest. With early bladder emptying, the effective dose equivalent of a 370 MBq adult study was about 1.5 mSv in volunteers, and the label advises drinking fluids and voiding often for six hours to reduce the dose to the bladder wall, the organ that receives the most. The label lists no contraindications or warnings; adverse reactions reported include nausea, vomiting, breathing difficulty, itching, rash, fast heart rate, raised blood pressure, chills, fever and seizure.
Technetium Tc 99m mertiatide is prepared and given only in nuclear medicine departments, by staff trained to handle radioactive material. The activities below are the label's; they are measured in megabecquerels of radioactivity, not in milligrams, and are not something anyone could prepare.
Mechanism of Action
Technetium-99m MAG3 is a tracer, not a treatment: it follows the kidney's own route for secreting anions, and the gamma rays from technetium-99m let a camera follow it.
Bound in plasma, released to the tubules
About 89% is protein-bound after injection, reversibly, so little is filtered; it is removed mainly by active tubular secretion with some glomerular filtration (label, Clinical Pharmacology).
Secreted by the tubules
Its kidney extraction is high and its clearance tracks hippuran's at about half to two thirds of its value, reported as the tubular extraction rate (PMIDs 2965116, 2143528).
Imaged by gamma camera
Technetium-99m emits a 140.5 keV gamma ray and decays with a 6.02-hour half-life, giving sharp images at low radiation dose (label, Physical Characteristics).
Out in the urine
In healthy people nearly 90% is in urine within three hours, against about 21% in severe kidney impairment (label); some is excreted in bile, more so when kidney function is poor (PMIDs 11545186, 41524526).
Published Research
The studies behind technetium-99m MAG3, read from their PubMed abstracts: its synthesis and first tests in animals and volunteers, its pharmacokinetics and radiation dose, comparisons with hippuran and DTPA, a review, and recent studies of what MAG3 scans can and cannot show in transplants, children and adults.
Synthesis as a hippuran replacement
The new N3S chelator MAG3 gave a single technetium-99m product that was excreted almost only by the kidneys in mice, cleared faster than hippuran in rats (2.84 against 2.17 mL/min/100 g) and had an extraction efficiency of 85% against 69%.
First volunteers: MAG3 against hippuran
In ten healthy volunteers, MAG3 images were clearly better than iodine-131 hippuran's, renogram peaks came at the same time and about 73% of the dose was in urine by 30 minutes, supporting it as a technetium replacement for hippuran.
Clinical evaluation and the TER
In 48 patients, many after kidney transplantation, MAG3 renograms matched hippuran's in shape, and its clearance correlated with hippuran's (r = 0.95) at a mean ratio of 0.65; the authors named its clearance the tubular extraction rate.
Pharmacokinetics in patients
Compared with hippuran, MAG3 had higher protein binding, higher concentration in blood, a smaller distribution volume and about two thirds of its clearance, with similar biological half-lives; measurements during surgery found no elimination outside the kidney.
Radiation dose in volunteers
From biodistribution in healthy volunteers, the effective dose equivalent was 3.7 mSv per 370 MBq with voiding every 4.8 hours and 1.5 mSv with voiding at 30 minutes and every 4 hours; early voiding can halve or third the gonadal dose.
Captopril scans for renal artery stenosis
In 102 hypertensive patients compared with angiography, MAG3 scans after 50 mg captopril detected stenoses over 50% with 89.6% sensitivity and 91.6% specificity, using 120 MBq.
Estimating renal plasma flow
In 103 subjects given MAG3 and hippuran together, MAG3 plasma clearance averaged 0.49 of hippuran's, but effective renal plasma flow from one could be predicted from the other in routine practice.
Transplants with poor function
In three transplant patients with stable but impaired function, MAG3 images were better than technetium-99m DTPA's in all, and in one the DTPA study was potentially misleading.
Fourteen years of MAG3
A review describes MAG3's higher protein binding, slower blood clearance, higher tubular extraction and more biliary excretion than hippuran, and its role as the agent of choice for renal, diuresis, captopril and transplant scintigraphy.
Reference values from 247 normal scans
From normal MAG3 scans in patients aged 25 days to 88 years, the authors set age-banded reference values for time to peak and the 20-minute to peak count ratio, consistent with earlier studies.
Early transplant dysfunction against biopsy
In 25 transplants with a biopsy, scans read as acute tubular necrosis were 93% sensitive but 70% specific, and only half of rejection episodes were identified; biopsy remained necessary when rejection was suspected.
Day-6 TER predicts transplant outcome
In 488 kidney recipients scanned on day 6, the lowest quartile of tubular extraction rate carried 9.45 times the odds of delayed graft function and, over 8.4 years, more rejection and graft failure or death.
Infants with suspected UPJ obstruction
In 37 infants under 3 months scanned twice with diuretic MAG3 renography, delayed tissue tracer transit did not predict later decline in split function, and agreement between local and central readers was poor.
Reading cortical defects
In 100 adult and 200 paediatric renograms, agreement between three observers on cortical defects was about 78-80%, falling to 62-65% when kidney-to-background ratio was 2 or less.
A scoring system for pyeloplasty
In 188 children with antenatal hydronephrosis, a renogram score combining split function, curve type and washout half-time predicted pyeloplasty (AUC 0.97), with a score of 5 fully specific.
Propofol sedation can mislead
In three sedated children, propofol, which alters kidney blood flow, produced diuresis renograms that looked abnormal but were judged nondiagnostic.
Liver excretion mimicking a urine leak
In a transplant recipient with severe graft dysfunction, MAG3 excreted through the liver appeared beside the kidney on delayed images and was traced by SPECT/CT to an ostomy bag, not a leak.
Probenecid and PAH slow its uptake
In healthy volunteers, p-aminohippurate and probenecid, which compete for the kidney's organic anion transporters, delayed MAG3 clearance from blood and reduced kidney uptake, so renal plasma flow estimated from the scan was underestimated; in cells it was carried mainly by OAT1.
Dosing Data
Technetium Tc 99m mertiatide is dosed in radioactivity, measured in a calibrator just before injection by nuclear medicine staff. The label's activities are below.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
The approved product, as its label describes it:
- Technescan Mag3 (technescan tc 99m mertiatide injection): Technescan MAG3 is supplied as a lyophilized powder packaged in vials. Each reaction vial contains 1 mg betiatide, 0.05 mg (minimum) stannous chloride dihydrate (SnCl 2.
Source: Technescan Mag3 (technescan tc 99m mertiatide injection) label, How Supplied (DailyMed version 9, effective January 6, 2026).
Mixing a vial: a worked example
Nothing to mix at home, and no syringe units to work out: Technetium Tc 99m mertiatide is a radioactive drug, prepared and given in nuclear-medicine departments, and its dose is an amount of radioactivity (MBq or GBq), not a weight.
This page's dosing note: “There is nothing to mix or calculate outside a nuclear medicine department.”
Source: this page's own note in Dosing Data below; the amount of each dose row in Dosing Data below.
Storage before and after mixing
Unknown: the label on file for Technetium Tc 99m mertiatide (Technescan Mag3 (technescan tc 99m mertiatide injection) label, sections 16 and 2 (DailyMed version 9, effective January 6, 2026)) has no storage sentence we could read. It is a radioactive drug held by the nuclear-medicine department that prepares and gives it (see the part above); the home rules for a mixed vial in the mixing guide do not apply to it.
How it is taken
As the approved label gives it: Intravenous injection (Single injection per study; Label: adults (70 kg), renal function and imaging).
Source: Manufacturer's recommended dosing (FDA label): the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: a half-life of No elimination half-life stated on the label: nearly 90% of the dose is in urine within 3 hours in healthy subjects (plasma clearance about 0.3 L/min); technetium-99m decays with a 6.02-hour physical half-life. After about five half-lives almost none is left.
How long the doses were given: Label: adults (70 kg), renal function and imaging: One scan; Label: children: One scan.
When effects appear: unknown; no source on this page gives a time to effect for Technetium Tc 99m mertiatide. Results reported in the studies are under Published Research.
Source: half-life: Technescan MAG3 (kit for the preparation of technetium Tc 99m mertiatide) US prescribing information (Curium US LLC; DailyMed set 0571c18b, version 9, effective January 6, 2026; read October 30, 2026), Clinical Pharmacology and Physical Characteristics; Manufacturer's recommended dosing (FDA label), the duration of each row in Dosing Data below.
Side effects, and when to stop or get help
From the Side Effects section: Reported adverse reactions: nausea, vomiting, wheezing, shortness of breath, itching and rash (label); Also reported: fast heart rate, raised blood pressure, shaking chills, fever and seizure (label); Radiation: about 1.5-3.7 mSv effective dose equivalent per 370 MBq depending on how soon the bladder is emptied (PMID 1530968); The bladder wall receives the highest organ dose (label, Radiation Dosimetry); Drugs that block the kidney's organic anion transporter OAT1, such as probenecid, reduce its uptake and can make kidney function look worse than it is (PMID 23618840). Full list and cautions ↓
When to stop or get help: unknown; the label's warnings summary we read gives no rule for stopping Technetium Tc 99m mertiatide. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the label's Adverse Reactions section and the studies above”).
Interactions
- p-aminohippurate (PAH) and probenecid (organic anion transporter inhibitors): slower blood clearance and lower kidney uptake of MAG3 in healthy volunteers, so renal plasma flow estimated from the scan was underestimated
Every peptide's record, with its source: the interaction matrix.
Source: human study, PMID 23618840.
Checking what you bought
Unknown: no published independent test of Technetium Tc 99m mertiatide products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder; it checks the measured mass against Technetium Tc 99m mertiatide's expected mass, 418.2 Da, from this entry's molecular data. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: FDA Approved (Approved in the US as Technescan MAG3 (kit for the preparation of technetium Tc 99m mertiatide), NDA 019882, on June 15, 1990, now held by Curium). Sport: Not on the 2026 List.
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
From the label's Adverse Reactions section and the studies above.
Contraindications & Cautions
From the Technescan MAG3 label (DailyMed set 0571c18b, version 9, effective January 6, 2026).
Legal Status
Technetium Tc 99m mertiatide is an approved prescription radiopharmaceutical in the US, supplied as kits to nuclear medicine departments.
Frequently Asked Questions
?What is a MAG3 scan?
A nuclear medicine scan of the kidneys. A small amount of technetium-99m MAG3 is injected into a vein and a gamma camera records how each kidney takes it up and drains it into the bladder over about half an hour.
?Why is it called a peptide?
Its ligand, mercaptoacetyltriglycine, is a chain of three glycines with a mercaptoacetyl group on the end, which holds the technetium atom. It is a tiny peptide derivative, not a hormone or a drug that acts on receptors.
?How much radiation does it give?
In volunteers an adult study of 370 MBq gave an effective dose equivalent of about 1.5 mSv when the bladder was emptied early, and about 3.7 mSv when it was not. Drinking and voiding often afterwards lowers it.
?Is it safe for babies?
It is widely used in infants with hydronephrosis, but the label says safety and effectiveness under 30 days of age have not been established.
?Why MAG3 rather than DTPA?
MAG3 is taken up mainly by tubular secretion, while DTPA is filtered. In transplant patients with impaired kidney function, MAG3 images were better than DTPA's in a direct comparison.
?Can I buy it?
No. It is made in hospital radiopharmacies from kits and injected by nuclear medicine staff.
References
- [pubmed] Fritzberg AR, et al. "Synthesis and biological evaluation of technetium-99m MAG3 as a hippuran replacement." J Nucl Med, 1986;27(1):111-6. PMID: 2934521.
- [clinical-trial] Taylor A Jr, et al. "Comparison of iodine-131 OIH and technetium-99m MAG3 renal imaging in volunteers." J Nucl Med, 1986;27(6):795-803. PMID: 2940350.
- [pubmed] Bubeck B, et al. "Technetium-99m labeled renal function and imaging agents: II. Clinical evaluation of 99mTc MAG3 (99mTc mercaptoacetylglycylglycylglycine)." Int J Rad Appl Instrum B, 1988;15(1):109-18. PMID: 2965116.
- [pubmed] Bubeck B, et al. "Pharmacokinetics of technetium-99m-MAG3 in humans." J Nucl Med, 1990;31(8):1285-93. PMID: 2143528.
- [pubmed] Stabin M, et al. "Radiation dosimetry for technetium-99m-MAG3, technetium-99m-DTPA, and iodine-131-OIH based on human biodistribution studies." J Nucl Med, 1992;33(1):33-40. PMID: 1530968.
- [pubmed] Dondi M. "Captopril renal scintigraphy with 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) for detecting renal artery stenosis." Am J Hypertens, 1991;4(12 Pt 2):737S-740S. PMID: 1837995.
- [pubmed] Bagni B, et al. "99mTc-MAG3 versus 131I-orthoiodohippurate in the routine determination of effective renal plasma flow." J Nucl Med Allied Sci, 1990;34(2):67-70. PMID: 2147211.
- [pubmed] Taylor A Jr, et al. "Comparison of Tc-99m MAG3 and Tc-99m DTPA in renal transplant patients with impaired renal function." Clin Nucl Med, 1990;15(6):371-8. PMID: 2141307.
- [review] Itoh K. "99mTc-MAG3: review of pharmacokinetics, clinical application to renal diseases and quantification of renal function." Ann Nucl Med, 2001;15(3):179-90. PMID: 11545186.
- [pubmed] Eilsberger F, et al. "Reference values for quantitative parameters in renal scintigraphy with Tc-99m-MAG3." Nuklearmedizin, 2020;59(4):316-322. PMID: 32227315.
- [pubmed] Imam A, et al. "Diagnostic Performance of 99mTc-MAG3 Renal Scintigraphy for Acute Tubular Necrosis and Acute Rejection in Kidney Transplant Recipients with Suspected Graft Dysfunction During the First 90 Days: A Single-Center, Biopsy-Referenced Retrospective Study." Diagnostics (Basel), 2026;16(19). PMID: 42882348.
- [pubmed] Buckenmayer A, et al. "Tubular MAG3 Extraction Rate is a Predictor of Short-Term and Long-Term Outcome After Kidney Transplantation: A Prospective Observational Study." Clin Nucl Med, 2026;51(3):203-210. PMID: 41468499.
- [clinical-trial] Luithle T, et al. "Determination of tissue tracer transit of Technetium-99m-mercaptoacetyltriglycine diuretic renography in infants with suspected ureteropelvic junction obstruction - A multicenter prospective observational study." J Pediatr Urol, 2023;19(6):780.e1-780.e7. PMID: 37718234.
- [pubmed] Hashlan M, et al. "Assessment of the interobserver and the intraobserver reproducibility for the detection of renal cortical defects in adults and children using [99mTc]Tc-MAG3." Q J Nucl Med Mol Imaging, 2025;69(3):243-250. PMID: 39869360.
- [pubmed] Hodhod A, et al. "Can we improve the usefulness of the diuretic renogram in the diagnosis of ureteropelvic junction obstruction (UPJO) in children? Introduction of mercaptoacetyltriglycine-suspected obstruction scoring system (MAG-SOS)." J Pediatr Urol, 2023;19(3):311.e1-311.e8. PMID: 36922332.
- [pubmed] Singh KB, et al. "Nondiagnostic 99m Tc-MAG3 Diuresis Renography Studies Caused by Propofol Sedation : A Case Series." Clin Nucl Med, 2024;49(10):984-986. PMID: 38717260.
- [pubmed] Zheng J, et al. "Hepatobiliary Excretion of 99m Tc-MAG3 on Renal Scintigraphy : A Diagnostic Pitfall in the Evaluation of Urine Leak." Clin Nucl Med, 2026;51(3):278-280. PMID: 41524526.
- [clinical-trial] Takahara N, et al. "Drugs interacting with organic anion transporter-1 affect uptake of Tc-99m-mercaptoacetyl-triglycine (MAG3) in the human kidney: therapeutic drug interaction in Tc-99m-MAG3 diagnosis of renal function and possible application of Tc-99m-MAG3 for drug development." Nucl Med Biol, 2013;40(5):643-50. PMID: 23618840.
- [fda-pi] Technescan MAG3 (kit for the preparation of technetium Tc 99m mertiatide) US prescribing information (Curium US LLC; DailyMed set 0571c18b, version 9, effective January 6, 2026; read October 30, 2026), Indications, Dosage and Administration, Clinical Pharmacology, Adverse Reactions, Precautions and Radiation Dosimetry.
- [other] US FDA, Drugs@FDA (openFDA drugsfda endpoint), read October 30, 2026: NDA 019882 Technescan MAG3 (Curium), original approval June 15, 1990; ANDA 208994 (Sun Pharmaceutical Industries, approved July 12, 2019), ANDA 206489 (Medi-Radiopharma, approved February 6, 2020) and NDA 216820 (Jubilant Draximage, approved January 30, 2023), all kits for technetium Tc 99m mertiatide, prescription.
- [other] ChEMBL CHEMBL2111131 (technetium Tc 99m mertiatide; synonyms Technescan MAG3, TC-MAG3): full molecular formula C8H8N3Na2O6STc (disodium salt), molecular weight 418.21. Read October 30, 2026. https://www.ebi.ac.uk/chembl/compound_report_card/CHEMBL2111131/
Sources & Citations
Every study on this page was read from its PubMed record on October 30, 2026. Doses, adverse reactions, cautions and kinetics come from the Technescan MAG3 label on DailyMed (set 0571c18b, version 9, effective January 6, 2026), read the same day; approvals from Drugs@FDA and the formula from ChEMBL. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.