CPT code 78121: Red cell mass, multiple determinations2026 Medicare rate & RVUs in Arizona
Reports a nuclear medicine study that determines circulating red cell mass using multiple measurements, often during evaluation of erythrocytosis.
In Arizona, Medicare pays $94.64 for 78121 in the office.
Check a contract rate as a % of Medicare · 78121 nationwide
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 11 sections
What 78121 covers
This study measures the amount of red blood cells circulating in the patient’s body. It commonly involves labeling the patient’s red cells, returning them to circulation, and obtaining multiple measurements from blood samples. Nuclear medicine staff perform the technical work, and a qualified physician interprets the results. The test may help evaluate whether an elevated red cell count reflects increased red cell mass or another cause, such as reduced plasma volume.
Select this code when the performed study includes multiple red cell mass determinations; use the single-determination code when only one is performed. Documentation should identify the study performed, its multiple measurements, and the physician’s interpretation. CMS recognizes professional and technical components: modifier 26 identifies interpretation, modifier TC identifies equipment and staff, and billing without either modifier represents the global service. Modifiers 26 and TC are separately priced.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
How Arizona compares for 78121
Across 109 of 109 payment localities, the office rate for 78121 runs from $84.66 in Arkansas to $135.69 in San Benito County, CA. Arizona pays $94.64. The RVUs are the same everywhere; the geographic indexes change the dollars.
- Arizona · this page$94.64
- Los Angeles, CA · California$113.04+$18.40
- Washington, DC area · District of Columbia$113.50+$18.86
- Miami, FL · Florida$103.59+$8.95
- Chicago, IL · Illinois$100.19+$5.55
- Manhattan, NY · New York$113.02+$18.38
- Alaska · Alaska$107.52+$12.88
Other areas in Arizona first, then benchmark localities. Bars start at $0.
Every other payment area
| Payment locality | Office | Facility |
|---|---|---|
| AlabamaAlabama | $86.12 | — |
| ArkansasArkansas | $84.66 | — |
| Bakersfield, CACalifornia | $105.28 | — |
| Chico, CACalifornia | $105.14 | — |
| El Centro, CACalifornia | $105.15 | — |
| Fresno, CACalifornia | $105.14 | — |
| Hanford, CACalifornia | $105.14 | — |
| Madera, CACalifornia | $105.14 | — |
| Merced, CACalifornia | $105.14 | — |
| Modesto, CACalifornia | $105.14 | — |
| Napa, CACalifornia | $124.55 | — |
| Oxnard, CACalifornia | $112.75 | — |
| Redding, CACalifornia | $105.14 | — |
| Rest of CaliforniaCalifornia | $105.14 | — |
| Riverside, CACalifornia | $105.68 | — |
| Sacramento, CACalifornia | $111.07 | — |
| Salinas, CACalifornia | $110.67 | — |
| San Diego, CACalifornia | $113.84 | — |
| Marin County, CACalifornia | $132.67 | — |
| San Francisco, CACalifornia | $132.61 | — |
| San Benito County, CACalifornia | $135.69 | — |
| Santa Clara County, CACalifornia | $135.46 | — |
| San Luis Obispo, CACalifornia | $108.82 | — |
| Santa Cruz, CACalifornia | $115.36 | — |
| Santa Maria, CACalifornia | $111.24 | — |
| Santa Rosa, CACalifornia | $116.56 | — |
| Stockton, CACalifornia | $105.14 | — |
| Vallejo, CACalifornia | $124.47 | — |
| Visalia, CACalifornia | $105.14 | — |
| Yuba City, CACalifornia | $105.14 | — |
| ColoradoColorado | $102.76 | — |
| ConnecticutConnecticut | $104.67 | — |
| DelawareDelaware | $96.39 | — |
| Fort Lauderdale, FLFlorida | $99.99 | — |
| Rest of FloridaFlorida | $94.61 | — |
| Atlanta, GAGeorgia | $99.27 | — |
| Rest of GeorgiaGeorgia | $88.62 | — |
| Hawaii, Guam, HIHawaii | $108.54 | — |
| IowaIowa | $89.26 | — |
| IdahoIdaho | $89.81 | — |
| East St. Louis, ILIllinois | $92.38 | — |
| Rest of IllinoisIllinois | $91.03 | — |
| Suburban Chicago, ILIllinois | $101.20 | — |
| IndianaIndiana | $90.43 | — |
| KansasKansas | $88.49 | — |
| KentuckyKentucky | $87.90 | — |
| New Orleans, LALouisiana | $92.71 | — |
| Rest of LouisianaLouisiana | $87.63 | — |
| Metropolitan Boston, MAMassachusetts | $114.36 | — |
| Rest of MassachusettsMassachusetts | $101.89 | — |
| Baltimore area, MDMaryland | $104.33 | — |
| Rest of MarylandMaryland | $98.52 | — |
| Rest of MaineMaine | $90.06 | — |
| Southern Maine, MEMaine | $96.14 | — |
| Detroit, MIMichigan | $95.68 | — |
| Rest of MichiganMichigan | $90.31 | — |
| MinnesotaMinnesota | $98.83 | — |
| Metropolitan Kansas City, MOMissouri | $92.28 | — |
| Metropolitan St. Louis, MOMissouri | $93.43 | — |
| Rest of MissouriMissouri | $85.69 | — |
| MississippiMississippi | $85.21 | — |
| MontanaMontana | $97.53 | — |
| North CarolinaNorth Carolina | $91.20 | — |
| North DakotaNorth Dakota | $96.54 | — |
| NebraskaNebraska | $89.91 | — |
| New HampshireNew Hampshire | $100.83 | — |
| Northern New JerseyNew Jersey | $111.98 | — |
| Rest of New JerseyNew Jersey | $105.97 | — |
| New MexicoNew Mexico | $90.77 | — |
| NevadaNevada | $97.34 | — |
| NYC suburbs and Long Island, NYNew York | $115.79 | — |
| Poughkeepsie and northern NYC suburbs, NYNew York | $106.47 | — |
| Queens, NYNew York | $114.49 | — |
| Rest of New YorkNew York | $92.76 | — |
| OhioOhio | $90.10 | — |
| OklahomaOklahoma | $88.01 | — |
| Portland, OROregon | $106.76 | — |
| Rest of OregonOregon | $96.69 | — |
| Metropolitan Philadelphia, PAPennsylvania | $101.55 | — |
| Rest of PennsylvaniaPennsylvania | $90.43 | — |
| Puerto RicoPuerto Rico | $98.45 | — |
| Rhode IslandRhode Island | $100.37 | — |
| South CarolinaSouth Carolina | $90.78 | — |
| South DakotaSouth Dakota | $96.42 | — |
| TennesseeTennessee | $88.98 | — |
| Austin, TXTexas | $102.32 | — |
| Beaumont, TXTexas | $89.72 | — |
| Brazoria, TXTexas | $96.48 | — |
| Dallas, TXTexas | $97.04 | — |
| Fort Worth, TXTexas | $96.21 | — |
| Galveston, TXTexas | $96.73 | — |
| Houston, TXTexas | $97.64 | — |
| Rest of TexasTexas | $93.01 | — |
| UtahUtah | $92.23 | — |
| VirginiaVirginia | $95.59 | — |
| Virgin Islands, VIUnited States Virgin Islands | $98.45 | — |
| VermontVermont | $95.85 | — |
| Rest of WashingtonWashington | $101.80 | — |
| King County, WAWashington | $117.15 | — |
| WisconsinWisconsin | $92.78 | — |
| West VirginiaWest Virginia | $87.05 | — |
| WyomingWyoming | $97.10 | — |
78121 rates by state
Office rate range in each state. Select a state to see its payment localities.
Explore a state
Local rates. Clear comparisons.
Hover or focus a tile to see its rate range. Select it to open the state’s fee schedule.
$84.66
$120.41
Color shows the midpoint of each state’s locality range.
View every state and territory as a table
| State / territory | Office rate range | Localities |
|---|---|---|
| AK | $107.52 | 1 |
| AL | $86.12 | 1 |
| AR | $84.66 | 1 |
| AZ | $94.64 | 1 |
| CA | $105.14–$135.69 | 29 |
| CO | $102.76 | 1 |
| CT | $104.67 | 1 |
| DC | $113.50 | 1 |
| DE | $96.39 | 1 |
| FL | $94.61–$103.59 | 3 |
| GA | $88.62–$99.27 | 2 |
| GU | $108.54 | 1 |
| HI | $108.54 | 1 |
| IA | $89.26 | 1 |
| ID | $89.81 | 1 |
| IL | $91.03–$101.20 | 4 |
| IN | $90.43 | 1 |
| KS | $88.49 | 1 |
| KY | $87.90 | 1 |
| LA | $87.63–$92.71 | 2 |
| MA | $101.89–$114.36 | 2 |
| MD | $98.52–$113.50 | 3 |
| ME | $90.06–$96.14 | 2 |
| MI | $90.31–$95.68 | 2 |
| MN | $98.83 | 1 |
| MO | $85.69–$93.43 | 3 |
| MS | $85.21 | 1 |
| MT | $97.53 | 1 |
| NC | $91.20 | 1 |
| ND | $96.54 | 1 |
| NE | $89.91 | 1 |
| NH | $100.83 | 1 |
| NJ | $105.97–$111.98 | 2 |
| NM | $90.77 | 1 |
| NV | $97.34 | 1 |
| NY | $92.76–$115.79 | 5 |
| OH | $90.10 | 1 |
| OK | $88.01 | 1 |
| OR | $96.69–$106.76 | 2 |
| PA | $90.43–$101.55 | 2 |
| PR | $98.45 | 1 |
| RI | $100.37 | 1 |
| SC | $90.78 | 1 |
| SD | $96.42 | 1 |
| TN | $88.98 | 1 |
| TX | $89.72–$102.32 | 8 |
| UT | $92.23 | 1 |
| VA | $95.59–$113.50 | 2 |
| VI | $98.45 | 1 |
| VT | $95.85 | 1 |
| WA | $101.80–$117.15 | 2 |
| WI | $92.78 | 1 |
| WV | $87.05 | 1 |
| WY | $97.10 | 1 |
How the 78121 rate is calculated
Each of 78121’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 78121
RVUs × geographic indexes × conversion factor
Work0.31
0.31 RVUs× 1.000 GPCI
Practice expense2.56
2.56 RVUs× 1.000 GPCI
Malpractice0.05
0.05 RVUs× 1.000 GPCI
Adjusted RVUs
2.9200
Conversion factor
$33.4009
Medicare rate
$97.53
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
The exact Arizona inputs and CMS source lines
PPRRVU2026_Oct_nonQPP.csv
9,233
- Code
- 78121
- Physician work
- 0.31
- Practice expense
- 2.56
- Malpractice
- 0.05
GPCI2026.csv
6
- Locality
- Arizona
- Physician work
- 1.000
- Practice expense
- 0.969
- Malpractice
- 0.856
| Component | RVU | Locality factor | Adjusted |
|---|---|---|---|
| Physician work | 0.31 | × 1.000 | 0.3100 |
| Practice expense | 2.56 | × 0.969 | 2.4806 |
| Malpractice | 0.05 | × 0.856 | 0.0428 |
| Total RVUs | 2.8334 | ||
| Conversion factor | × 33.4009 | ||
Office rate, Arizona$94.64
Office: (0.31 × 1 + 2.56 × 0.969 + 0.05 × 0.856) × $33.4009 = $94.64
Payment rules and modifiers for 78121
The CMS indicators that decide how 78121 is paid alongside other services.
CMS payment indicators · 78121
Red cell mass, multiple determinations
| Rule | CMS value | What it means |
|---|---|---|
| Global period | XXX | The global surgery concept doesn’t apply. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 1 | Diagnostic test with separate professional (26) and technical (TC) components. |
What modifiers do to the payment
Modifier 26 · payment effect
With and without the modifier
78121 without 26 · national office
$97.53
Red cell mass, multiple determinations
78121-26 · Professional component
$14.70
Pays only the interpretation and report.
How 78121 has changed in Arizona
78121 · Office / nonfacility
$94.64
Effective 2026-10-01
The base rate is $5.32 higher than on 2025-10-01, moving from $89.32 to $94.64 (6.0%).
It is unchanged from the immediately preceding available release, effective 2026-07-01.
One bar per available release, ordered by effective date. Missing rates remain gaps. These comparisons hold the code, setting and locality identifiers constant; they do not isolate which policy or input caused a change.
What changed, release by release
January 1, 2026
RVU26A
$89.32changed to$94.64
- Conversion factor 32.3465 changed to 33.4009
- Work RVU 0.32 changed to 0.31
- Practice expense RVU 2.46 changed to 2.56
- Practice expense GPCI 0.975 changed to 0.969
- Malpractice GPCI 0.854 changed to 0.856
Held through RVU26B, RVU26C, RVU26D.
January 1, 2025
RVU25A
$75.04changed to$89.32
- Conversion factor 33.2875 changed to 32.3465
- Practice expense RVU 1.94 changed to 2.46
Held through RVU25B, RVU25C, RVU25D.
March 9, 2024
RVU24AR
$73.81changed to$75.04
- Conversion factor 32.7442 changed to 33.2875
Held through RVU24B, RVU24C, RVU24D.
January 1, 2024
RVU24A
$75.27changed to$73.81
- Conversion factor 33.8872 changed to 32.7442
- Practice expense RVU 1.93 changed to 1.94
- Practice expense GPCI 0.963 changed to 0.975
- Malpractice GPCI 0.855 changed to 0.854
January 1, 2023
RVU23A
$76.73changed to$75.27
- Conversion factor 34.6062 changed to 33.8872
- Practice expense RVU 1.95 changed to 1.93
- Practice expense GPCI 0.951 changed to 0.963
- Malpractice GPCI 0.857 changed to 0.855
Held through RVU23B, RVU23C, RVU23D.
January 1, 2022
RVU22A
$77.04changed to$76.73
- Conversion factor 34.8931 changed to 34.6062
- Practice expense RVU 1.94 changed to 1.95
Held through RVU22B, RVU22C, RVU22D.
January 1, 2021
RVU21A
$77.63changed to$77.04
- Conversion factor 36.0896 changed to 34.8931
- Practice expense RVU 1.87 changed to 1.94
- Malpractice RVU 0.04 changed to 0.05
- Practice expense GPCI 0.961 changed to 0.951
- Malpractice GPCI 0.846 changed to 0.857
Held through RVU21B, RVU21C, RVU21D.
January 1, 2020
RVU20A
$78.17changed to$77.63
- Conversion factor 36.0391 changed to 36.0896
- Practice expense GPCI 0.971 changed to 0.961
- Malpractice GPCI 0.834 changed to 0.846
Held through RVU20B, RVU20C, RVU20D.
January 1, 2019
RVU19A
$86.83changed to$78.17
- Conversion factor 35.9996 changed to 36.0391
- Practice expense RVU 2.12 changed to 1.87
Held through RVU19B, RVU19C, RVU19D.
January 1, 2018
RVU18AR1
$107.55changed to$86.83
- Conversion factor 35.8887 changed to 35.9996
- Practice expense RVU 2.68 changed to 2.12
- Practice expense GPCI 0.986 changed to 0.971
- Malpractice GPCI 0.856 changed to 0.834
Held through RVU18B, RVU18C, RVU18D.
January 1, 2017
RVU17A
$106.12changed to$107.55
- Conversion factor 35.8043 changed to 35.8887
- Practice expense RVU 2.60 changed to 2.68
- Malpractice RVU 0.05 changed to 0.04
- Practice expense GPCI 1.000 changed to 0.986
- Malpractice GPCI 0.877 changed to 0.856
Held through RVU17B, RVU17C, RVU17D.
January 1, 2016
RVU16A
$109.46changed to$106.12
- Conversion factor 35.9335 changed to 35.8043
- Practice expense RVU 2.70 changed to 2.60
- Malpractice RVU 0.03 changed to 0.05
Held through RVU16B, RVU16C, RVU16D.
July 1, 2015
RVU15C
$108.92changed to$109.46
- Conversion factor 35.7547 changed to 35.9335
Held through RVU15D.
January 1, 2015
RVU15A
$101.39changed to$108.92
- Conversion factor 35.8228 changed to 35.7547
- Practice expense RVU 2.50 changed to 2.70
- Malpractice RVU 0.04 changed to 0.03
- Practice expense GPCI 0.989 changed to 1.000
- Malpractice GPCI 0.946 changed to 0.877
Held through RVU15B.
January 1, 2014
RVU14A
$77.82changed to$101.39
- Conversion factor 34.0230 changed to 35.8228
- Practice expense RVU 1.97 changed to 2.50
- Practice expense GPCI 0.978 changed to 0.989
- Malpractice GPCI 1.015 changed to 0.946
Held through RVU14B, RVU14C, RVU14D.
January 1, 2013
RVU13AR
Earliest loaded release: $77.82
Held through RVU13B, RVU13C, RVU13D.
| Effective from | Office | Facility | CMS release |
|---|---|---|---|
| 2026-10-01 | $94.64 | Not available in this setting | RVU26D |
| 2026-07-01 | $94.64 | Not available in this setting | RVU26C |
| 2026-04-01 | $94.64 | Not available in this setting | RVU26B |
| 2026-01-01 | $94.64 | Not available in this setting | RVU26A |
| 2025-10-01 | $89.32 | Not available in this setting | RVU25D |
| 2025-07-01 | $89.32 | Not available in this setting | RVU25C |
| 2025-04-01 | $89.32 | Not available in this setting | RVU25B |
| 2025-01-01 | $89.32 | Not available in this setting | RVU25A |
| 2024-10-01 | $75.04 | Not available in this setting | RVU24D |
| 2024-07-01 | $75.04 | Not available in this setting | RVU24C |
| 2024-04-01 | $75.04 | Not available in this setting | RVU24B |
| 2024-03-09 | $75.04 | Not available in this setting | RVU24AR |
| 2024-01-01 | $73.81 | Not available in this setting | RVU24A |
| 2023-10-01 | $75.27 | Not available in this setting | RVU23D |
| 2023-07-01 | $75.27 | Not available in this setting | RVU23C |
| 2023-04-01 | $75.27 | Not available in this setting | RVU23B |
| 2023-01-01 | $75.27 | Not available in this setting | RVU23A |
| 2022-10-01 | $76.73 | Not available in this setting | RVU22D |
| 2022-07-01 | $76.73 | Not available in this setting | RVU22C |
| 2022-04-01 | $76.73 | Not available in this setting | RVU22B |
| 2022-01-01 | $76.73 | Not available in this setting | RVU22A |
| 2021-10-01 | $77.04 | Not available in this setting | RVU21D |
| 2021-07-01 | $77.04 | Not available in this setting | RVU21C |
| 2021-04-01 | $77.04 | Not available in this setting | RVU21B |
| 2021-01-01 | $77.04 | Not available in this setting | RVU21A |
| 2020-10-01 | $77.63 | Not available in this setting | RVU20D |
| 2020-07-01 | $77.63 | Not available in this setting | RVU20C |
| 2020-04-01 | $77.63 | Not available in this setting | RVU20B |
| 2020-01-01 | $77.63 | Not available in this setting | RVU20A |
| 2019-10-01 | $78.17 | Not available in this setting | RVU19D |
| 2019-07-01 | $78.17 | Not available in this setting | RVU19C |
| 2019-04-01 | $78.17 | Not available in this setting | RVU19B |
| 2019-01-01 | $78.17 | Not available in this setting | RVU19A |
| 2018-10-01 | $86.83 | Not available in this setting | RVU18D |
| 2018-07-01 | $86.83 | Not available in this setting | RVU18C |
| 2018-04-01 | $86.83 | Not available in this setting | RVU18B |
| 2018-01-01 | $86.83 | Not available in this setting | RVU18AR1 |
| 2017-10-01 | $107.55 | Not available in this setting | RVU17D |
| 2017-07-01 | $107.55 | Not available in this setting | RVU17C |
| 2017-04-01 | $107.55 | Not available in this setting | RVU17B |
| 2017-01-01 | $107.55 | Not available in this setting | RVU17A |
| 2016-10-01 | $106.12 | Not available in this setting | RVU16D |
| 2016-07-01 | $106.12 | Not available in this setting | RVU16C |
| 2016-04-01 | $106.12 | Not available in this setting | RVU16B |
| 2016-01-01 | $106.12 | Not available in this setting | RVU16A |
| 2015-10-01 | $109.46 | Not available in this setting | RVU15D |
| 2015-07-01 | $109.46 | Not available in this setting | RVU15C |
| 2015-04-01 | $108.92 | Not available in this setting | RVU15B |
| 2015-01-01 | $108.92 | Not available in this setting | RVU15A |
| 2014-10-01 | $101.39 | Not available in this setting | RVU14D |
| 2014-07-01 | $101.39 | Not available in this setting | RVU14C |
| 2014-04-01 | $101.39 | Not available in this setting | RVU14B |
| 2014-01-01 | $101.39 | Not available in this setting | RVU14A |
| 2013-10-01 | $77.82 | Not available in this setting | RVU13D |
| 2013-07-01 | $77.82 | Not available in this setting | RVU13C |
| 2013-04-01 | $77.82 | Not available in this setting | RVU13B |
| 2013-01-01 | $77.82 | Not available in this setting | RVU13AR |
Where the Arizona rate applies
Arizona is a Medicare payment area, not a city. Our Census mapping connects it to 467 cities and communities in Arizona. Some span more than one payment area; confirm with the service ZIP.
- Aguila
- Ajo
- Ak Chin
- Ak-Chin Village
- Alamo Lake
- Ali Chuk
- Ali Chukson
- Ali Molina
78121 billing questions
When should 78121 be chosen instead of 78120?
Use 78121 when the red cell mass study involves multiple determinations. Use 78120 when the study involves a single determination.
Does “multiple” mean the test was repeated on another date?
It refers to multiple determinations in the performed study, not simply a later repeat of the test. The record should support that the study included multiple measurements.
How should the professional and technical portions be billed?
Report modifier 26 for the physician’s interpretation or modifier TC for the technical service. Without either modifier, the claim represents the global service.
Can plasma volume testing be reported with this study?
A plasma volume determination is a separate measurement from red cell mass and may be performed as part of a blood-volume assessment. The record should support each service reported.
What documentation supports 78121?
Document the red cell mass study, the multiple determinations performed, and the physician’s interpretation. The technical record should support the equipment and staff services when the TC portion is billed.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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